Every NFL Team's Biggest X-Factor for 2021
Not to make this sound like the beginning of a middle school essay, but the Merriam-Webster Dictionary defines an X-factor as a "person that has a strong but unpredictable influence."
That would be a fair way to describe a lot of NFL players, but every team has to have an ultimate X-factor.
In many cases, you could broadly declare that any unproven starting quarterback fits the bill, but that's a little too obvious. We all know every starting signal-caller will have a massive influence.
Last offseason, B/R's Brent Sobleski figured there were three types of X-factors: individuals who have yet to reach their full potential, rookies who could contribute at a higher level than their draft status indicates, and established veterans stepping into new situations with the need to reestablish themselves.
I'll add that a "new situation" doesn't need to be a new team. And I'll also consider young players who in fact have lived up to expectations but could become superstars in 2021.
These are players who aren't starting quarterbacks or prototypical stars but whose performances this season could explain why the teams they play for either make the Super Bowl or miss the playoffs entirely.
With that in mind, here are 32 prime X-factors for the upcoming NFL campaign.
Arizona Cardinals: LB Isaiah Simmons
There were several top-notch X-factor candidates for an Arizona Cardinals team that is good enough to make a Super Bowl run but still mysterious enough to fail to post a winning record for the sixth year in a row.
Newcomer J.J. Watt could put them over the top if he can stay healthy and productive at 32, but that's a big "if." Fellow pass-rusher Chandler Jones is in a similar boat coming off a significant biceps injury, so they're hoping established veterans Malcolm Butler and Rodney Hudson can make impacts in a new setting at cornerback and center, respectively, and a lot is riding on third-year second-round corner Byron Murphy to take the next step.
But then there's linebacker Isaiah Simmons, who came along slowly as a rookie No. 8 overall pick in 2020. The versatile 22-year-old Clemson product has All-Pro potential as a playmaker, but we saw very little of that as he was on the field for just 34 percent of Arizona's defensive snaps and failed to stand out when he was out there in 2020.
If he can take off following a more regular offseason, it could really help the Cards get over the top. But another quiet season from such a high draft pick would be a blow.
Atlanta Falcons: WR Calvin Ridley
The Julio Jones era is over for the Atlanta Falcons, and the clear-cut "next man up" is Calvin Ridley, so he's the obvious 2021 X-factor here.
After all, Ridley was an important cog even with Jones in the WR1 spot the last few seasons. He went over 800 yards in his first two seasons before exploding with 1,374 in 2020, and he's scored at least seven touchdowns in all three of his pro campaigns.
But the Falcons haven't experienced much team success since drafting Ridley in the first round in 2018, and he's struggled with drops and consistency at times.
There's lots of hype surrounding rookie tight end Kyle Pitts in Atlanta, but it often takes tight ends time to get acclimated to the pro game. The majority of the pressure is on Ridley outside.
Baltimore Ravens: EDGE Tyus Bowser
When the Baltimore Ravens let veteran edge defenders Matt Judon and Yannick Ngakoue escape in free agency but re-signed 2017 second-round pick Tyus Bowser, it became obvious they believed Bowser still has a shot at becoming an elite pass-rusher in this league.
And while he's flown under the radar for much of his first four seasons, that's entirely possible. The 26-year-old picked up five sacks in a supporting role in 2019 and registered a strong 22 pressures and 14 quarterback hits as a part-time player in 2020.
He also intercepted three passes and recorded five passes defended, so there's some definite playmaking ability there for a player who has never been on the field for more than 51 percent of Baltimore's defensive snaps.
If Bowser breaks out in 2021, the Ravens will greatly increase their chances of getting past the Divisional Playoffs for the first time in the Lamar Jackson era. But if he doesn't deliver, they could be in big trouble sans Judon and Ngakoue.
Buffalo Bills: Pick a Running Back, Any Running Back
This might seem like somewhat of a cop-out, but that's how open the competition appears to be in the Buffalo Bills' offensive backfield. After ranking 22nd in DVOA (defense-adjusted value over average from Football Outsiders) on the ground during quarterback Josh Allen's breakout 2020 season, they desperately need one of their backs to make a consistent impact in 2021.
That could mean 2020 third-round pick Zack Moss, 2019 third-rounder Devin Singletary or veteran free-agent addition Matt Breida, or possibly even a longshot like Taiwan Jones, Antonio Williams or Christian Wade.
Singletary compiled nearly 1,000 scrimmage yards last season but struggled in the playoffs, Moss gained steam late in his rookie year before suffering a significant ankle injury in January, and Breida had some moments with the San Francisco 49ers but failed to take the reins last year with the Miami Dolphins.
As a group, they edge out wild-card pass-rusher A.J. Epenesa (who could play a larger role but might still be stuck behind veterans Jerry Hughes and Mario Addison on the edge) and offensive lineman Cody Ford (who has the talent to become special but might not need to for the offense to flourish).
Carolina Panthers: EDGE Haason Reddick
Whoever wins the starting left tackle job left vacant by unsigned veteran Russell Okung could wind up emerging as the ultimate X-factor for the Carolina Panthers, but that job remains up for grabs, and we don't want to turn this into an "X-position" exercise.
So instead, let's focus on Carolina's newest edge presence, veteran pass-rusher Haason Reddick.
Brian Burns emerged as a first-round sophomore with nine sacks in 2020, but the jury's still out on 2020 second-round selection Yetur Gross-Matos, and Reddick should be expected to play a major role regardless.
The 2017 No. 13 overall pick posted an incredible 7.5 sacks and forced six fumbles in the final four games of his fourth pro season with the Cardinals, and now we'll find out if that was a fluke or a sign of things to come for a talented dude who struggled for much of that four-year run in Arizona.
The Panthers had a bottom-10 pass defense in terms of DVOA last year, so they need him to deliver.
Chicago Bears: CB Jaylon Johnson
The increasingly desperate Chicago Bears took several notable risks this offseason, with the team's decision to trade up in Round 1 for quarterback Justin Fields standing out. But the Bears also essentially kept free-agent wide receiver Allen Robinson at the expense of two-time Pro Bowl cornerback Kyle Fuller, who was a salary-cap casualty in March.
And while they at least added the experienced Desmond Trufant on the open market, Fuller's departure will put a lot of pressure on sophomore corner Jaylon Johnson.
The 2020 second-round pick flashed quite a bit in 13 starts as a rookie, but he didn't intercept any passes, and he ultimately surrendered a triple-digit passer rating on throws into his coverage. Still, 15 passes defended despite missing three games as a 21-year-old rookie could be a sign that Johnson has a bright future, and the Bears likely feel that way based on their decision to part with Fuller.
Nobody is questioning Chicago's front-seven talent, but the secondary will likely have to start pulling more weight if the Bears are to have a shot in the NFC North in 2021. The pass defense ranked in the middle of the pack in DVOA last season, but a breakout campaign or a sophomore slump from Johnson could send that rank shooting in either direction.
Cincinnati Bengals: OT Jonah Williams
When the Cincinnati Bengals passed on blue-chip offensive tackle Penei Sewell in favor of wide receiver Ja'Marr Chase with the No. 5 overall pick in the draft, they made a statement about 2019 first-round pick Jonah Williams.
The left tackle out of Alabama missed his rookie season as a result of a shoulder injury and was forced to catch up during a 2020 offseason that was severely limited by the COVID-19 pandemic, but he gave up just three sacks and took merely two penalties during a solid debut season as a starter, according to Pro Football Focus.
Still, the Bengals line was a mess and 2020 No. 1 overall pick Joe Burrow was not adequately protected. If that's going to change in 2021, it'll fall first and foremost on Williams, who has All-Pro potential and will at least have some more support with steady veteran Riley Reiff and second-round rookie Jackson Carman joining the fray.
That positions Williams as Cincinnati's ultimate X-factor. New defensive assets Chidobe Awuzie and Trey Hendrickson are worth mentioning as they try to provide upgrades over the departed William Jackson III and Carl Lawson at corner and on the edge, respectively, but the Bengals will be made or broken on offense.
Cleveland Browns: EDGE Jadeveon Clowney
The Cleveland Browns don't need incoming veteran edge defender Jadeveon Clowney to be their best pass-rusher, but they need him to remove some of the burden from do-it-all All-Pro Myles Garrett.
Olivier Vernon's gone and no other player on the Browns roster recorded more than a single sack with the team in 2020, but they invested in Clowney and another veteran first-round pick, Takkarist McKinley, in free agency, and they're obviously hoping one or both can pick it up for a defense that ranked in the bottom 10 against the pass and overall in DVOA despite the presence of Garrett last year.
Clowney is a three-time Pro Bowler and an exceptional playmaker with supreme versatility, so the 2014 No. 1 overall pick will almost certainly have first dibs on that starting role opposite Garrett. But he hasn't been himself while almost becoming a journeyman the last few years.
He might have just three sacks the last two seasons, but this setting could be ideal for Clowney to recapture past glory. Keep in mind that he's still only 28 years old. If he can put it together in 2021, he could put the Browns over the top.
Dallas Cowboys: EDGE Randy Gregory
Randy Gregory recorded more quarterback hits for the Dallas Cowboys last season than anybody currently on the Dallas roster. That despite the fact the 2015 second-round pick played in just 10 games, didn't make a single start and was on the field for just 25 percent of the team's defensive snaps.
That goes to show how disappointing the highly paid Demarcus Lawrence was yet again, but also how much potential Gregory possesses if he can keep it together on and off the field.
That, of course, has been a huge problem for the tantalizing former Nebraska star. Injuries and off-field issues have kept him from becoming a consistent presence thus far in his career. Now, at 28, he's on track to start a season in good standing with the league for just the second time in the last six years.
A bottom-10 Dallas defense in terms of DVOA needs more from Lawrence but also more punch across the board on that side of the ball. With Aldon Smith gone, a breakout year from Gregory could be a game-changer for the Cowboys.
Of course, it's hard to give him the benefit of the doubt at this stage.
Denver Broncos: TE Noah Fant
If the Denver Broncos are going to make Drew Lock or Teddy Bridgewater work at quarterback, they're going to need to get the most out of an arsenal that is plagued by question marks right now.
How will top receiver Courtland Sutton bounce back from a torn ACL? Can Jerry Jeudy improve after a drop-heavy rookie season? And can Noah Fant take a step forward after hitting somewhat of a wall as a sophomore in 2020?
Jeudy and Fant are particularly strong candidates here, but we'll roll with the 2019 first-round tight end because he's a year ahead of Jeudy and he could serve as more of a safety valve for whoever wins the quarterback job in Denver.
Fant is a remarkable athlete in a position that usually requires some time for acclimation at the NFL level. He's scored just six touchdowns in two years but he did finish strong with 181 yards in the last three games of his second season. A breakout 2021 campaign could be huge for a Broncos team that is already strong defensively but needs more from the passing game.
Detroit Lions: CB Jeff Okudah
We'll give Detroit Lions cornerback Jeff Okudah a pass for a rough rookie season because the circumstances were brutal as a result of the pandemic. But when you're a corner drafted third overall, the leash can only be so long.
With Desmond Trufant and Justin Coleman following Darius Slay out the door in Detroit, so much will inevitably fall on Okudah's shoulders in 2021. That's scary because the Ohio State product surrendered a 118.0 passer rating into his coverage in limited action as a rookie, but also exciting because you have to be pretty damn special to be drafted that high as a defensive back.
Special he is. Okudah has the size, instincts and resume to become an All-Pro cover man. Now, a Lions pass defense that ranked dead-last in DVOA last season needs him to take off. So he's easily the guy over third-year tight end T.J. Hockenson, who is a lot more of a sure-thing after a Pro Bowl sophomore campaign.
Green Bay Packers: EDGE Rashan Gary
There's little doubt that as long as reigning MVP Aaron Rodgers returns, the Green Bay Packers will rack up points in 2021. But the defense remains a question mark after a so-so season in which they ranked in the middle of the pack against the pass and run in DVOA.
With that in mind, it'd sure be nice if 2019 first-round pick Rashan Gary were to explode in his third season as a pass-rusher.
The Packers have brought Gary along slowly because of the presence of well-paid veterans Za'Darius Smith and Preston Smith on the edge, but he had five sacks despite starting four games in 2020 while Preston settled for four sacks despite starting 13. The Michigan product is still just 23 years old, and a strong playoff performance against the Los Angeles Rams in January could indicate he's set to break out.
If that happens and he and Za'Darius Smith become an elite duo on the edge, the Packers could be a lot better positioned for a Super Bowl run than they were in 2020. But if Smith struggles again and Gary can't improve, it could be problematic.
Houston Texans: OT Tytus Howard
There's so much up in the air with the Houston Texans right now that it's difficult to identify a potential X-factor, but it's hard to imagine such a flawed team excelling regardless of other circumstances without a strong third season from offensive tackle Tytus Howard.
The 2019 first-round pick has started just 22 games thus far in his NFL career, 14 of which came during an inconsistent sophomore campaign in which he was penalized 11 times, according to PFF. He's 25 now, so another disappointing season would be concerning.
But if he can live up to his talent in 2021, he and Pro Bowler Laremy Tunsil could form one of the best tackle combos in the league.
That'd be huge for the Texans regardless of their quarterback situation, which is why Howard is in this spot rather than a player like Shaq Lawson, whom they're counting on to break out in a new setting but who likely can't make as much of a difference considering the many questions about the Houston defense.
Indianapolis Colts: S Julian Blackmon
An argument can be made that whoever is responsible for Carson Wentz's blind side in place of the retired Anthony Castonzo during Wentz's critical debut season with the Indianapolis Colts will be the team's X-factor in 2021.
The problem is it's still too early to know if veteran addition Eric Fisher will be healthy enough to play that role from the get-go, which could leave them leaning more heavily on the rest of an accomplished line while unreliable vet Sam Tevi likely steps in.
The line is strong in general, though, which is another reason why we'll instead look at a sophomore third-round defensive back who flashed often as a rookie and could easily become a star in Year 2.
Julian Blackmon had two interceptions, six passes defended, 42 tackles (three for a loss) and a forced fumble as a rookie safety, but those numbers don't fully tell the story of his impact. He was seemingly always in on big plays, and the Colts felt good enough about him this offseason that they basically ignored the safety position in free agency and the draft.
Indy's defense is strong, but most of the star power is in the front seven. If Blackmon can change that next season, that D could get to the next level. But if he suffers a sophomore slump, they could be in a lot of trouble.
Jacksonville Jaguars: OTs Cam Robinson and Jawaan Taylor
We're cheating here and giving you two relatively young second-round picks who will start at the same critical position and be charged with making sure Trevor Lawrence's rookie season is less dangerous than Joe Burrow's was with the Bengals in 2020.
PFF ranked the Jacksonville Jaguars' offensive line in the bottom 12 last year, and much of that had to do with the fact that offensive tackles Cam Robinson, 25, and Jawaan Taylor, 23, didn't get the job done.
But the Jags are rolling with the status quo for Lawrence. They somewhat surprisingly hit Robinson with the franchise tag, and they seem to be hoping Taylor can break out in his third season. They did draft offensive tackle Walker Little in Round 2, but he's got a small college sample and a large injury history, so they're putting most of their eggs in baskets belonging to Robinson and Taylor.
If both can put it together in Urban Meyer's offense, Lawrence will have a good chance of meeting expectations as a rookie No. 1 overall pick. If not, he could be running for his life for much of 2021.
Kansas City Chiefs: OL Lucas Niang
This is another case in which it feels as though the entire offensive line could be an X-factor. We all saw what happened to Patrick Mahomes and the Kansas City Chiefs when the line was in shambles against the Tampa Bay Buccaneers in Super Bowl LV.
But let's zero in on an intriguing 2020 Day 2 pick who opted out last year but could have a shot at multiple starting spots this offseason.
"He's done a nice job in this camp," Chiefs head coach Andy Reid said of Niang in a virtual press conference during the team's rookie minicamp. "He's a big man—like really, a big man—that has these beautiful feet. So I look forward to getting him back in the pads in training camp: moving around, doing what offensive linemen do—the real football part of it."
He's 6'6", 315 pounds, and his college tape is eye-popping. In a perfect world for K.C., he easily beats out journeyman Mike Remmers to earn a starting spot opposite incoming Pro Bowler Orlando Brown Jr., but he could also have a shot at the right guard spot opposite steady addition Joe Thuney.
If he can pull off either feat and excel, Mahomes could be golden in 2021.
Las Vegas Raiders: EDGE Yannick Ngakoue
The Las Vegas Raiders recorded just 15 takeaways and 21 sacks last season, ranking in the bottom five in the NFL in both categories. The defense is actually quietly loaded with young but unproven talent, especially in the secondary. But to make it all work, you get the feeling the unit's newest established veteran will have to excel.
That veteran is Yannick Ngakoue, who signed a two-year, $26 million contract in March and has the playmaking ability to transform that defensive front.
The 26-year-old has recorded 45.5 sacks and 18 forced fumbles in five professional seasons. Only future Hall of Famer Khalil Mack has forced more fumbles during that span, and he, Mack and Aaron Donald are the only players with at least eight sacks in each of the past five NFL campaigns.
That said, it's a bit of a red flag that he's on his fourth roster in less than a year. He's a boom-or-bust player who could make or break the Raiders' D.
Los Angeles Chargers: S Derwin James
With reigning Offensive Rookie of the Year Justin Herbert now protected by a bolstered offensive line, there's no denying the trajectory of the Los Angeles Chargers offense. But questions continue to surround a defense that ranked in the bottom 12 in DVOA in 2020.
If the Bolts are going to hang with Mahomes and the Chiefs and, if a trade happens, possibly even Rodgers and the Broncos in 2021, they'll need more from that unit. That includes help for elite pass-rusher Joey Bosa up front (ideally from young first-round picks Jerry Tillery and Kenneth Murray as well as Melvin Ingram III replacement Uchenna Nwosu), but the key might be a bounce-back year from Derwin James in the secondary.
The 2018 first-round pick was dominant as a first-team All-Pro rookie with three picks, 3.5 sacks and 105 tackles, but he's missed all but five games since then. However, he's back on the field without limitations.
If the 24-year-old can get back on the track he was on in 2018, the Chargers could skyrocket in the defensive rankings. If not, the secondary is likely to be a liability in 2021.
Los Angeles Rams: S Jordan Fuller
Instead of Jordan Fuller, this could easily have been Taylor Rapp, Terrell Burgess or JuJu Hughes. The point is, the Los Angeles Rams need a solid safety now that standout veteran John Johnson III is in Cleveland.
We're rolling with Fuller because he appears to have the best chance to make an impact as a full-time starter after he intercepted three passes in 12 starts as a rookie sixth-round pick in 2020.
Was that a sign that he's a steal, or was it a fluke? And how will he hold up without Johnson or steady slot corner Troy Hill, who also joined the Browns in March?
The Rams D has to be about more than just Aaron Donald and Jalen Ramsey, but they've been bleeding talent in recent offseasons. It was still a top-four unit against both the pass and run at Football Outsiders in 2020, but for that to continue, Fuller might have to shine even more in 2021.
Miami Dolphins: OT Austin Jackson
The Miami Dolphins invested heavily in Tua Tagovailoa's offensive line in last year's draft, with Austin Jackson representing that investment at the critical left tackle spot. But even though Jackson's rookie season was rocky, as he posted a replaceable 52.3 grade at PFF, the Dolphins indicated they believe in him by passing on opportunities to add tackles this offseason.
Sure, they drafted Liam Eichenberg in Round 2, but if anything, that could lead to Eichenberg taking over at right tackle, with Robert Hunt kicking inside.
Jackson, Hunt, Eichenberg, incoming veteran center Matt Skura, sophomore guard Solomon Kindley and the entire offensive line should be considered the X-factor in Tua's crucial second season under center, but it still starts with Jackson.
If the 21-year-old No. 18 overall pick out of USC can make a leap in year two, the Dolphins offense could kill it and Tagovailoa will have a good chance of staying healthy. But that remains a big "if."
Minnesota Vikings: OT Christian Darrisaw
For the Minnesota Vikings, this came down to a rookie offensive tackle charged with making an immediate impact on Kirk Cousins' blind side and a veteran pass-rusher looking to bounce back from a lost season on the edge.
You could argue that Danielle Hunter doesn't qualify because he was a star already with Pro Bowl seasons in 2018 and 2019, so we gave the edge to 2021 first-round pick Christian Darrisaw.
Considering that Cousins, running back Dalvin Cook and wideout Adam Thielen are expensive and in win-now mode, Darrisaw faces a huge responsibility as the presumed Week 1 starter at left tackle in Minnesota. The Vikings can't afford to wait out growing pains for long, but they also lack quality alternatives besides regular starting right tackle Brian O'Neill.
The good news is Darrisaw is a physical marvel who should be NFL-ready as a three-year starter at left tackle in college. The bad news is he's already missed some time with a groin injury.
New England Patriots: WR Nelson Agholor
The New England Patriots reinforced their roster in a lot of key spots this offseason in hopes of making a return to Super Bowl conversations in 2021, but one significant concern is the receiving corps.
That unit had issues even before Julian Edelman retired, and the Patriots focused on the offensive line and tight end group in free agency. That means Nelson Agholor could be on track to land WR1 duties after signing a two-year, $22 million contract in the offseason.
That's scary because the 2015 first-round pick was an inconsistent, unreliable disappointment in Philadelphia before he spent just one season in Las Vegas. That year with the Raiders was, however, his most productive yet with 896 yards and eight touchdowns.
Can the Patriots enable him to complete his redemption at age 28? He's in a good spot for such things, but he still has a lot of trust to earn. If he can finally live up to expectations, the Pats offense could explode regardless of whether Cam Newton or rookie Mac Jones is at quarterback. But that's certainly not guaranteed.
New Orleans Saints: EDGE Marcus Davenport
Pass-rusher Trey Hendrickson exploded with 13.5 sacks in a breakout 2020 season for the New Orleans Saints, just in time to earn a lucrative long-term contract elsewhere in free agency. Meanwhile, perennial Pro Bowler Cameron Jordan saw his sack total decline significantly during his age-31 season.
With Hendrickson gone, the Saints sorely need support for the aging Jordan, and that'll fall first on 2018 first-round pick Marcus Davenport.
The Saints also used their first-round pick on edge defender Payton Turner and signed another (Tanoh Kpassagnon) in free agency, but the former might need time and the latter doesn't have Davenport's pedigree.
The 2018 No. 14 pick has lacked durability, consistency and playing time (he's never been on the field for more than 50 percent of New Orleans' defensive snaps), but the Saints obviously believe in him after picking up his fifth-year option this offseason.
With the offense likely to take a hit post-Drew Brees, it's imperative that Davenport takes off at age 24 to bolster the D.
New York Giants: OT Andrew Thomas
Take what we said about Austin Jackson and the Dolphins and replace Tagovailoa with Daniel Jones, Jackson with Andrew Thomas and the Dolphins with the New York Giants.
Thomas, Jones' left tackle, was even more of a disappointment than Jackson as a rookie No. 4 pick. The powerful Georgia product was dominant in college before surrendering 10 sacks in 2020, according to PFF.
Jones has a lot of fresh support with targets Kenny Golladay, Kadarius Toney, John Ross III and Kyle Rudolph joining the offense and running back Saquon Barkley returning from a torn ACL, but the Giants didn't address the line much in the offseason. If they're going to take off in what might be a make-or-break season for their third-year quarterback, Thomas will need to improve substantially as a sophomore on the blind side.
New York Jets: WR Corey Davis
There were several great nominees for the rebuilding New York Jets, who will need strong seasons in support of rookie quarterback Zach Wilson from new receiver Corey Davis, sophomore second-round pass-catcher Denzel Mims and young offensive linemen Mekhi Becton and Alijah Vera-Tucker.
On defense, they need linebacker C.J. Mosley to return to stardom after basically two full years away from the game because of injury and then a 2020 opt-out, and they could use a jolt from new pass-rusher Carl Lawson.
All are arguably X-factors to various degrees, but Davis stands out because he's Wilson's best shot at a No. 1 receiver after the wideout inked a three-year, $37.5 million contract in the offseason.
The 2017 No. 5 overall pick failed to live up to his draft status with the Tennessee Titans but had a career-best 984 yards and five touchdowns in 2020. The Jets desperately need him to build on that in a new setting.
Philadelphia Eagles: RB Miles Sanders
Miles Sanders was widely projected to become a fantasy football star and a leading contributor to the Philadelphia Eagles in 2021. Instead, the running back was limited by injuries while averaging fewer yards per touch than he had as a rookie in 2019.
Quarterback issues didn't help either, but Sanders will enter his third campaign following a proper offseason, during which he'll have gotten plenty of work in with presumed Eagles starting signal-caller Jalen Hurts.
Will that be enough for Sanders to put together his first 1,000-yard season as a rusher? Will it help him regain the strong receiving numbers that highlighted his maiden season? We'll soon find out. But if the exciting second-round pick out of Penn State doesn't bolster his numbers significantly in 2021, it might never happen and the Eagles will likely struggle to keep up in the NFC East.
Offensive tackle Andre Dillard is another strong candidate, but he still has to earn a starting role over Jordan Mailata, so we're going with a locked-in RB1 who faces a lot of pressure to produce.
Pittsburgh Steelers: OTs Chukwuma Okorafor and Zach Banner
We cheated by listing both starting offensive tackles for the Jaguars, and we're doing it again for the Pittsburgh Steelers.
An argument could be made that first-round rookie running back Najee Harris is the ultimate X-factor for a Pittsburgh team in desperate need of a jolt to remain a contender in 2021. But this will almost certainly remain a pass-first team under gunslinger quarterback Ben Roethlisberger, and both the tackles will have to hold up in unfamiliar territory.
Chukwuma Okorafor had his share of struggles in place of injured right tackle Zach Banner last year, but with Banner returning and two-time Pro Bowler Alejandro Villanueva gone, Okorafor will move to Big Ben's blind side.
Is the 2018 third-round pick ready for that? And how will the huge and tantalizing but still unproven Banner (6'8", 335 lbs) bounce back from a lost season due to a torn ACL? If both players shine, it could make it possible for Roethlisberger, Harris and Co. to keep the Steelers in contention. But the opposite could easily happen as well.
San Francisco 49ers: WR Deebo Samuel
You could argue that Jimmy Garoppolo, Deebo Samuel, George Kittle and Nick Bosa are all X-factors for the San Francisco 49ers, considering that they're crucial players coming off injury-derailed seasons. But we have a no-starting quarterback rule, and Kittle and Bosa feel a little too established, considering their incredible 2019 campaigns.
So while there's a little more margin for error with Samuel because of the presence of second-year first-round pick Brandon Aiyuk at wide receiver, we'll go with Garoppolo's favorite non-Kittle target from 2019.
It'll be hard for Kittle to excel to the best of his superstar ability and for Aiyuk to evolve as a sophomore if Samuel can't stay healthy and pick up in 2021 where he left off during a promising rookie campaign in 2019.
The 49ers are stacked in a lot of spots, but a lot rests on Samuel's shoulders. It's hard to envision them rebounding from a brutal 2020 if he isn't a big factor next season.
Seattle Seahawks: G Gabe Jackson
The Seattle Seahawks' X-factor is a soon-to-be 30-year-old guard?
That's how important it is that the Seahawks keep frustrated quarterback Russell Wilson clean. They invested in Gabe Jackson this offseason for that exact reason, and the respected veteran will have to deliver alongside promising 2020 rookie Damien Lewis, established tackle Duane Brown and fellow presumed starters Brandon Shell and Ethan Pocic in 2021.
Jackson, who came over via trade from the Raiders in March for a fifth-rounder, has been a steady starter since entering the league as a third-round pick in 2014. He should be an upgrade over the retired Mike Iupati inside. But if the Raiders nailed the timing here and Jackson's hitting a wall after seven seasons, the gamble could backfire on Seattle with little margin for error along the offensive line.
That's why he beats out young recent first-round picks L.J. Collier and Jordyn Brooks. Those guys have a lot to prove but are at least surrounded by a fair amount of talent and depth up front on the Seattle defense.
Tampa Bay Buccaneers: OT Tristan Wirfs
It's damn hard to defend a title, mainly because it's hard for anyone to improve when so many are on top of their games during that initial Super Bowl season. But the Tampa Bay Buccaneers relied heavily on two rookies in particular in 2020, and there's little reason to believe both offensive tackle Tristan Wirfs and safety Antoine Winfield Jr. won't improve immensely in 2021.
Both could be considered X-factors, but protecting Tom Brady is pretty much the most important job in Tampa, and the Buccaneers might not have won that Lombardi Trophy without Wirfs.
Per PFF, the physically dominant 22-year-old was responsible for just one sack throughout the regular season and playoffs. And according to Pro Football Reference, he was flagged for holding just twice all year.
The Bucs absolutely need the 2020 No. 13 pick out of Iowa to avoid any sort of sophomore slump next season. The same goes for Winfield, but there's less on his shoulders considering the talent surrounding him on defense.
Tennessee Titans: EDGE Bud Dupree
Enter Bud Dupree, an obvious X-factor if Tennessee is going to get over the hump and make a Super Bowl run with Derrick Henry and Ryan Tannehill in their primes.
The Titans are rolling the dice that the veteran edge defender can resurrect their pass rush after they handed him a five-year, $82.5 million deal this offseason. And while Dupree is a strong, established presence on the edge who has 18.5 sacks in his last 24 games, we've rarely seen him as a No. 1 pass-rusher and haven't seen him at all since he tore his ACL in December.
Even if 2019 first-round pick Jeffery Simmons emerges up front for the Tennessee D in 2021, it's difficult to imagine the Titans competing when it counts if Dupree doesn't play like a Pro Bowl-caliber edge-rusher.
Washington Football Team: QB Taylor Heinicke
That's right, the X-factor for the Washington Football Team this season is a presumed backup quarterback.
Ryan Fitzpatrick is likely to be the Week 1 starter, but the WFT's ceiling is pretty obvious with him under center. The experienced journeyman is solid in a pinch, but we have plenty of proof that he won't carry anybody to a Super Bowl.
In 16 NFL seasons, Fitzpatrick has never started a playoff game. He's inconsistent, and his impact has always been limited. That will almost certainly be the case again in his age-39 season.
That's why Washington desperately needs Heinicke to win this job, either this summer or some time in the fall before it's too late. The 28-year-old doesn't have much experience or pedigree, but he looked impressive in Washington's playoff loss to the Bucs in January. There might be something there, and if that's the case and he can take the league by storm in 2021, a defensively stacked Washington team could be legit.