Breaking Down 15 of the NFL's Most Likely Day 1 Rookie Starters

C.J. Mosley has already established himself as a starter on the Baltimore Ravens defense at inside linebacker.Larry French/Getty Images

Rookie-versus-veteran battles for starting jobs are currently happening throughout the NFL this preseason. And some 2014 draft picks, such as Buffalo Bills wide receiver Sammy Watkins and Baltimore Ravens linebacker C.J. Mosley, have already taken hold of first-team roles for their teams.

Each of the following 15 rookies will most likely, barring injuries or unforeseen setbacks, be in their respective teams’ lineups when they take the field for regular-season openers.

Now that the following players have asserted themselves as worthy starters (or, in some cases, have been placed there by default due to lack of viable/healthy competition), the focus turns to how they can contribute on the field and potentially make their teams better.

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The Houston Texans didn’t just draft Jadeveon Clowney to be a starter; they drafted him to be a star of their defense when they selected him with the No. 1 overall pick this May.

There’s little reason to think he won’t be. A 6’6”, 266-pound edge-defender who runs a 4.53 40-yard dash, Clowney is a near-superhuman physical specimen who can burst into the backfield in a flash and overwhelm blockers with both his quickness and power.

A defensive end at South Carolina, Clowney is transitioning to outside linebacker in the Texans’ 3-4 defensive scheme.

That transition might be his biggest hurdle to rookie stardom. Clowney’s already capable of bringing heavy pressure off the edge and shutting down run plays at the line of scrimmage. His inexperience in space and in coverage, however, could lead to some fallible moments early in his career.

With the addition of Clowney, no team in the NFL has a more exciting pairing of pass-rushers. Houston can line him up opposite two-time All-Pro defensive end J.J. Watt and have havoc-wreakers attacking both edges of the offensive line. The Texans can also line Clowney and Watt up alongside each other to force opposing offenses into single-team blocking matchups against the star defenders.

Clowney’s technique remains a work in progress, but his exceptional physical tools have already enabled him to make big plays this preseason. He is a favorite to win this year’s Defensive Rookie of the Year award.

Like the only player selected ahead of him, No. 2 overall pick Greg Robinson is also making a position change for his rookie season. After two excellent seasons at left tackle at Auburn, Robinson is slated to start inside at left guard, alongside veteran left tackle Jake Long, for the St. Louis Rams.

The move should enable Robinson to achieve immediate success in the NFL.

If you were building the ideal offensive lineman, his physical attributes would be quite close to Robinson's. A 6’5”, 322-pound giant who runs a 4.92 40-yard dash, Robinson has a combination of size, athleticism and power that has rarely been seen, even in the NFL.

The transition to guard certainly comes with a learning curve. For instance, he looked confused at times in St. Louis’ preseason opener versus the New Orleans Saints. But it can also protect against his biggest concern coming into the league: his ability to kick out in pass protection and shield the edge against outside pass-rushers.

Robinson can truly overpower his opponents as a drive-blocker, and he has an excellent burst to explode to the second level and pick up downfield blocks. He can utilize those traits to open up frequent inside lanes for Rams running backs this season.

As a pass-blocker, Robinson can use his strength and good leverage to keep inside rushers at bay. As long as he can consistently get his hands on penetrators and stunting rushers, he should dominate in that capacity as well.

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The Buffalo Bills traded their first- and fourth-round picks in next year’s draft to the Cleveland Browns to move up just five spots, to No. 4 overall, to select Clemson wide receiver Sammy Watkins. They wouldn’t have done that if they didn’t expect him to play an integral role in their offense from Day 1.

Already the No. 1 wide receiver on the Bills depth chart, Watkins gives Buffalo a potential star playmaker on the outside. He is a fast, natural strider who can beat defenders deep but also create big plays in the open field with his lateral quickness and ability to bounce off contact.

Watkins has very good physical tools, but he doesn’t simply rely on them to succeed.

He is a skilled route-runner whose sharp breaks make covering him a challenge. Watkins is great at tracking the ball in the air, and he is already earning a reputation for making spectacular catches in training camp, including a remarkable one-handed grab Vined earlier this week by WGRZ’s Jonah Javad.

Buffalo is going to expect Watkins to emerge as a go-to target for quarterback EJ Manuel as early as Week 1. The Bills should look to get him the ball not only on deep passes but also on short throws that give him room to make plays on the run.

Watkins gained experience on running plays as a multipurpose player at Clemson, and that’s certainly a skill the Bills could incorporate into their offensive game plan.

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The Oakland Raiders didn’t hesitate to make room for No. 5 overall pick Khalil Mack in their starting lineup. In their first organized team activity in May, Mack was already on the first-team defense at strong-side linebacker. Oakland moved Sio Moore to weak-side linebacker to replace Kevin Burnett, who would be released by the team in July.

Mack, the first-ever Round 1 pick from the University at Buffalo, is in no risk of losing his starting job. Although his first game this preseason was disappointing, Mack should play a key role in Oakland’s defensive plays throughout the 2014 season.

A do-it-all defender at Buffalo, Mack will be expected to provide pass-rushing pressure at times, drop back into coverage on other plays and cover ground in space as a run defender. A 6’3”, 251-pound linebacker with a 4.65 40-yard dash, Mack has the strength to hold up against blocks at the line of scrimmage but also the range to make plays from sideline to sideline.

While his primary responsibilities will come at the linebacker level, Mack is also expected to see playing time as a defensive end in nickel sub-packages, much like how Oakland’s division rivals, the Denver Broncos, utilize their own strong-side linebacker, Von Miller.

Mack could have some growing pains as a rookie as he learns his role in a 4-3 defense after working primarily out of a 3-4 scheme and mostly against Mid-American Conference offenses that had few NFL talents in college. That said, Mack’s explosive athleticism and well-rounded game should enable him to excel in that transition.

Having set an NCAA record with 16 career forced fumbles and tied an NCAA record with 75 career total tackles for loss, Mack is a proven playmaker. He is among the top candidates to be this year’s Defensive Rookie of the Year.

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A four-year starting offensive tackle at Texas A&M, Jake Matthews was immediately entrenched as the Atlanta Falcons’ first-team right tackle after they selected him with the No. 6 overall pick.

Having played on the right side in his first three seasons for the Aggies, Matthews is a polished blocker at the position. He is an athletic tackle who consistently has his body in sync, plays with proper pad level and has clean, quick footwork.

Matthews is at his best in pass protection, where he was regularly dominant in his collegiate career. He’s not overpowering as a run-blocker, but he uses his athleticism well to trap-block inside and pick up defenders downfield.

The son of Hall of Fame offensive lineman Bruce Matthews, he’s as physically gifted and technically sound as his accomplished family tree would lead one to expect. He’s more than capable of being a bookend tackle for the Falcons, perhaps to eventually switch to the left side like he did as a senior at Texas A&M.

Matthews’ first preseason outing was a major disappointment—he was called for two holding penalties and looked overwhelmed—but it would be a surprise if his play doesn’t quickly improve. He is expected, along with the return of Sam Baker at left tackle and the addition of veteran right guard Jon Asamoah, to solidify a Falcons offensive line that struggled in 2013.

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Much like the aforementioned Khalil Mack, Anthony Barr is a transitioning strong-side linebacker who is expected to play in a hybrid role for his defense as a rookie starter.

Drafted by the Minnesota Vikings with the No. 9 overall pick, Barr is listed as a starter on the team’s depth chart and worked as such in its preseason opener.

Measured at 6’5” and 255 pounds with a 4.66 40-yard dash, Barr has outstanding measurables. He has good closing speed and can cover significant ground in space, yet he also has the size to hang as an edge-defender on the line of scrimmage.

An accomplished pass-rusher at UCLA, Barr is likely to see significant playing time as a defensive end on the line of scrimmage in passing situations. Fast around the corner with some quality pass-rushing moves, Barr can be an immediate source of pressure for the Vikings defense.

Transitioning to Minnesota’s 4-3 scheme from playing in a 3-4 defense collegiately, Barr is a decent run defender at the second level but needs to become stronger to get off blocks and provide a consistent presence up front. He is also inexperienced in coverage, an area he will need to be able to make plays as the “Sam” linebacker.

Overall, Barr’s game remains raw. He should be able to take advantage of his physical attributes to make some impact plays as a rookie, but it’s likely he’s at least a year or two away from being a standout player.

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The Pittsburgh Steelers have not had a rookie be a Week 1 starter on their defense since Kendrell Bell in 2001, but they’ve been prepared to buck history ever since they selected Ohio State linebacker Ryan Shazier with the No. 15 overall pick in this year’s draft.

Listed as the starting weak-side inside linebacker on Pittsburgh’s depth chart, Shazier has been working with the first-team defense all summer.

A terrific all-around athlete, Shazier could add a significant playmaking presence to the Pittsburgh defense in his rookie year. A fluid and explosive mover in space, he is a strong tackler who can make plays all over the field.

Shazier is a very good coverage linebacker who also has experience bringing pressure on blitzes, so he should be a staple on every down and in all of Pittsburgh’s defensive packages.

At 6’1” and 237 pounds, Shazier is smaller than the prototypical player at his position. He could have some issues shedding bigger and stronger blockers, but it shouldn’t stop him from being a hard hitter and aggressive defender.

His ability to make plays was evident in his time with the Buckeyes. His range will allow the players around him, especially strong-side inside linebacker Lawrence Timmons, to focus more on their strengths and less on covering ground.

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Zack Martin started every game of his four-year Notre Dame career at offensive tackle, but the Dallas Cowboys drafted him with the No. 16 overall pick to play right guard, at least for 2014, and haven’t looked back.

Reportedly considered by some within the Cowboys organization to be “the most accomplished rookie they've ever seen,” according to Dan Turner of UKCowboysFans.com, Martin is expected to make the Cowboys much better at a position that has been a revolving door of struggling players in recent years.

Although Martin was an excellent tackle for the Fighting Irish, guard actually projects as his best position at the professional level.

He lacks the ideal length and athleticism of an NFL offensive tackle, but he makes up for it with great strength and exceptional technique.

Martin’s most outstanding skill is his hand placement; he is consistent and has only rarely been pushed back once he gets his mitts on a defender. He plays with good pad level, wins with leverage and has clean footwork.

Given the consistency of his play at Notre Dame, anything less than a solid rookie season would be a surprise. Unlike previous years when the Cowboys have too often given up pressure inside and failed to generate a significant push up front, Martin should—along with second-year center Travis Frederick—allow Dallas to be much more effective running inside and give quarterback Tony Romo a cleaner pocket.

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Although the Baltimore Ravens also have a promising second-year inside linebacker in 2013 second-round pick Arthur Brown, it’s already become clear that C.J. Mosley, the No. 17 overall pick in this year’s draft, has won the battle to start alongside Daryl Smith on the Ravens defense.

That’s not a surprise. A well-rounded playmaker who had four years of high production on talent-laden defenses at Alabama, Mosley is a perfect fit to take on a key role at the weak-side inside linebacker position on the Baltimore defense.

Mosley has tremendous instincts and the athleticism to act on them. He’s not the biggest or most explosive player, but he is a fluid mover and a consistent tackler in space.

An excellent coverage linebacker who had 24 passes defensed in his Crimson Tide career, Mosley is also a skilled blitzer who uses his hands effectively to work by blockers and disrupt plays in the backfield.

Mosley has been one of the most impressive rookies thus far this preseason, and he appears well on his way to a productive rookie season. Should he continue to be all around the ball in the first year of his NFL career, he could be Defensive Rookie of the Year.

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Replacing four starters on an offensive line that gave up a league-high 58 sacks in 2013, the Miami Dolphins had little choice but to draft a lineman with their first-round pick and make him a starter. They did so at No. 19 overall by selecting Tennessee’s Ja’Wuan James.

James, who started at right tackle for all four years of his collegiate career, is a natural fit to upgrade the Dolphins at that position, specifically where they need the help most in pass protection.

A 6’6”, 311-pound tackle with 35-inch arms, James is a strong blocker who consistently engages defenders within his wingspan and controls them with his hands.

He’s a nonexplosive athlete who has to be technically sound with his feet and rely on his length to capture outside pass-rushers, but he has been consistently solid on the edge both at Tennessee and in his preseason debut.

James is unlikely to ever be an impact run-blocker. He has not demonstrated much ability to drive opponents off the line of scrimmage, and he lacks the burst and quickness to do much damage at the second level.

Nonetheless, James will be worth the first-round investment Miami made in him if he can provide much-needed stability to an offensive line trying to recover from a 2013 season in disarray.

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All four wide receivers who caught passes for the Carolina Panthers during the 2013 regular season are no longer on the roster one year later, so the team's relying on new bodies—especially No. 28 overall pick Kelvin Benjamin—to step up as offensive playmakers.

At 6’5” and 240 pounds with 34.825-inch arms, Benjamin can create mismatches with even some of the NFL’s biggest defensive backs. A jump-ball target best known for his game-winning touchdown catch in Florida State’s BCS National Championship Game victory last season, Benjamin wins with his strength and leaping ability at the catch point.

He’s essentially a starter by default in Carolina, where he is lining up opposite veteran Jerricho Cotchery with the starters, but he’s earned it too. Labeled by ESPN.com’s David Newton as “the star of Panthers camp,” Benjamin has also already made the highlight reels as a Panther with his diving 29-yard touchdown catch in his preseason debut versus the Buffalo Bills.

Benjamin will need to develop as a route-runner to consistently separate against NFL defenders, as his 4.61 40-yard dash indicates limited speed and acceleration. But while he has to prove that he can be more than just a big target, his large frame increases his catch radius and allows him to make some plays even when covered.

It’s a stretch to expect greatness from Benjamin in his rookie year, but he clearly has the most playmaking potential of any wideout on Carolina’s roster. It’s important for the rookie to continue building a rapport with Panthers quarterback Cam Newton that can make them a productive passing combination in the regular season.

Johnny Manziel is the most prominent celebrity of the NFL’s rookie class, and Justin Gilbert was a top-10 overall pick, but the only Cleveland Browns rookie who is currently listed as a starter on their depth chart is second-round pick Joel Bitonio.

Bitonio “has been the starting left guard since training camp began,” according to Jeff Schudel of The News-Herald.

A left tackle at Nevada, the No. 34 overall pick has the foot skills to be a great fit in the offensive scheme run by new Browns offensive coordinator Kyle Shanahan, which emphasizes athleticism up front. Bitonio can move with plays, is an excellent pull-blocker and shoots off the line of scrimmage with burst.

At 6’4” and 302 pounds, Bitonio’s not a particularly big or powerful lineman, but he has strong hands and should hold up fine in pass protection so long as he continues to play with sound technique.

The transition to playing inside should have its growing pains for Bitonio, but he’s off to a good start. He was the Cleveland Browns’ highest-rated offensive player by Pro Football Focus (subscription required) in their preseason opener versus the Detroit Lions.

For an offense that could soon be built around Manziel, whose scrambling-heavy style of quarterback play makes it crucial to have athletic blockers up front who can give their signal-caller time to make a play, Bitonio looks to be an immediate upgrade on the interior line.

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With Justin Blackmon suspended indefinitely and Ace Sanders suspended for four games, No. 39 overall draft selection Marqise Lee has been propelled into the starting lineup at wide receiver for the Jacksonville Jaguars.

A smooth route-runner who accelerates naturally and glides in the open field, Lee could be an immediate-impact player both outside and from the slot as a rookie for the Jaguars.

Lee’s not the biggest or fastest receiver, but he has a proven ability to get open and track the ball into his hands. He had 248 receptions for 3,655 yards and 29 touchdowns in his three-year career at USC.

The rookie starter was subjected to criticism after his first preseason game, in which he went catchless, from Jacksonville coach Gus Bradley. Bradley told the media last week that Lee “could have done some things even more precise” and “wasn’t exactly where we need him to be” in the team’s opener versus the Tampa Bay Buccaneers, according to Ryan O’Halloran of The Florida Times-Union.

Lee, whose effort and focus were called into question by his coach, had a seemingly more pleasing effort Thursday night against the Chicago Bears as he caught four passes for 27 yards and a touchdown.

It’s unknown whether Jacksonville’s first-round pick, Blake Bortles, will be given a legitimate shot to unseat incumbent starter Chad Henne and be the quarterback primarily throwing to Lee on Sundays this fall. But as long as Lee keeps pushing himself to improve, he has the skills to emerge as a highly productive player on the Jaguars offense right away, regardless of who the team’s passer is.

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Jack Mewhort had a chance to beat out Donald Thomas for the starting left guard job anyway, but Thomas’ season-ending torn quadriceps muscle made Mewhort a clear choice to take his place in the lineup.

It’s not ideal for the Colts to have to turn to a late second-round pick to start up front without making him earn the job, but Mewhort should be more than capable of taking on the role and succeeding in his debut season.

The No. 59 overall pick from Ohio State is a strong, technically sound blocker who gained experience playing both tackle and guard over the course of his collegiate career.

He was a very good left tackle for the Buckeyes in his junior and senior seasons, but the move inside is one best suited for his talents. While he is a solid run-blocker who has clean footwork and rarely loses a battle once he gets his hands on an opponent, he lacks the lateral quickness to consistently handle outside speed-rushers.

That weakness will be hidden inside, where Mewhort should be able to take care of business in one-on-one matchups. He’s not a truly overpowering blocker, but he doesn’t often give up ground to defensive linemen either. His abilities to turn defenders at the line of scrimmage and to counter rush moves with his hands should enable him to be a very good if not great NFL guard.

Mewhort has no significant competition for the starting left guard job. If he is moved out of that spot at all, it might only be if the team needs him at center, where expected starter Khaled Holmes is battling an ankle injury.

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The Green Bay Packers depth chart lists third-round pick Richard Rodgers as the team’s fourth-string tight end, but that unofficial hierarchy of the roster seems to be more of a formality than it is accurate. All indications this summer have been that Rodgers has the inside track on a spot in Green Bay’s starting lineup.

An inconsistent performer at California who had just 59 career receptions and 896 receiving yards in college, Rodgers was seen as more of a long-term project than an instant fix when the Packers selected him with the No. 98 overall pick.

The Packers, however, seem to have other plans with Rodgers. Considered “an MVP of organized team activities” this spring by Tyler Dunne of the Milwaukee Journal Sentinel, Rodgers’ ascension as a playmaker has continued into the preseason.

He started at tight end for the Packers in their opener against the Tennessee Titans and made key plays as both a pass-catcher and blocker during his time in the game.

Rodgers came out of California as an unproven receiver and unpolished blocker, but he’s seemingly made great strides in both of those areas since being drafted. A big target at 6’4” and 257 pounds, Rodgers lacks top-end speed but could be a vertical threat in the middle of Green Bay’s offense nonetheless.

His competition for the starting job is likely to continue throughout the preseason with Brandon Bostick, who has been taking increased work with the first-team offense this week after a solid performance of his own against the Titans, according to ESPN.com’s Rob Demovsky.

Even so, it would seem that Rodgers, considering how quickly he has established himself as the potential best option in a relatively weak position group, is a good bet to be a Week 1 starter if he continues to make plays and show improvement over the course of Green Bay’s final three preseason games.

All measurables courtesy of NFL.com unless otherwise noted.

Dan Hope is an NFL/NFL Draft Featured Columnist for Bleacher Report.

Follow @Dan_Hope