Which Non-QBs Can NFL Franchises Least Stand to Lose in 2015?

Every quarterback going down will change a season. Not every non-quarterback will. 

Seahawks defensive tackle Brandon Mebane is a hell of a player. Losing him didn't do enough damage to keep Seattle out of the Super Bowl. Colts running back Ahmad Bradshaw was by far the best running back they had last season -- losing him did not impact their chances of winning the Super Bowl one iota. 

With that in mind, I've created this short list of non-quarterbacks who would devastate their teams if they went down to injury. Here's how I've defined that:

• Is this player actually great? Because, you know, it's hard to be irreplaceable if you're not terrific at your job. This is the starting point of any kind of subject like this.
• Who else does this team have to absorb the role this player currently fills? If, for instance, Clay Matthews gets hurt and misses the season, the Packers probably have enough pass rush to cover for his absence in Julius Peppers and Mike Daniels. They don't have a middle linebacker worth playing -- that we know about now -- but that's the reason I made him one of my last cuts.
• Does the projected absence of this player hurt the passing game or passing defense? Jamaal Charles going down would be devastating to the Chiefs, but they now have enough passing-game weapons in Jeremy Maclin and Travis Kelce to squint and kinda-sorta make it work with Knile Davis. You've got to be able to pass to win in the NFL. As the Patriots proved in the Super Bowl, you don't necessarily have to be able to run. 
• For extra points, is this player essentially the only good player in the section of the unit he currently plays in? I considered Panthers edge rusher Charles Johnson heavily for this list based solely on the idea that if he went down, I have no idea how the Panthers would get any pass rush. They've got Kony Ealy, yes, but projecting him to replace all that is a stretch. Ultimately, I found five players I liked better that fit the criteria, but it was close.

Let's begin the show...

5. Vontae Davis, Indianapolis Colts

Darron Cummings/Associated Press

• Is this player actually great?

Vontae Davis has been a talented player for a long time -- only in 2014 did he really step up and play the way he's been capable of since he entered the league. Last year was his first Pro Bowl, and since he was new to the party, he got cheated out of some All-Pro consideration that the more established players tend to get. He was Pro Football Focus' sixth-ranked player of 2014.

• Who else does this team have to absorb the role this player currently fills?

The Colts spent a third-round pick on cornerback D'Joun Smith, and they have steady players at corner who can play their scheme in Greg Toler and Darius Butler. They have nobody who can cover No. 1 receivers as Davis can. 

• Does the projected absence of this player hurt the passing game or passing defense?

Losing a No. 1 cornerback is not a deathblow to a pass defense unless it's someone as good as Darrelle Revis, but yes, the Colts would be severely compromised were Davis to go down. 

•  For extra points, is this player essentially the only good player in the section of the unit he currently plays in?

I would say yes, though I would add that there are definitely a number of potentially good players in Indianapolis' secondary. Safety Mike Adams could fight back the clock again and put up another good season. Butler and Toler have each had their moments. I really like the fit of fourth-round safety Clinton Geathers. 

But as far as players I not only think will do well, but expect will do well? That list begins and ends with Davis. 

4. Desmond Trufant, Atlanta Falcons

Marc Serota/Associated Press

• Is this player actually great?

Like Davis, Trufant took an important step forward in his development in 2014. Trufant doesn't have the "black ink" as Baseball Reference would put it yet -- no Pro Bowls, no All-Pros -- but he also played for the worst defense in the NFL in 2014. It was like putting Michael Phelps on a 100 meter medley team with you, Deb from accounting, and Fred Willard.

• Who else does this team have to absorb the role this player currently fills?

Great question. The Falcons spent a second-round pick on cornerback Jalen Collins out of LSU, and he has ideal physical qualities you look for in a top-of-the-line press cornerback. He also has almost no experience doing it and wasn't a starter at LSU. Which is why he was still available in the second round. Outside of that, the only cornerbacks on this roster with NFL playing time are Robert Alford, rumored to be moving to safety, and Philip Adams, a journeyman signed away from the Jets.

So, no. 

• Does the projected absence of this player hurt the passing game or passing defense?

Losing a No. 1 cornerback is not a deathblow to a pass defense unless it's someone as good as Darrelle Revis, but yes, the Falcons would be severely compromised were Trufant to go down. 

•  For extra points, is this player essentially the only good player in the section of the unit he currently plays in?

Absolutely. There's perhaps no darker place in the NFL right now than the Atlanta secondary depth chart minus Trufant. They were forced into starting sixth-round safety Kemal Ishmael right away. Dwight Lowery left in free agency, meaning that's likely to continue. Safety William Moore hasn't been healthy since the ink dried on his contract extension in 2013, and hasn't played up to the deal because of it. We've been over Alford and Collins. 

There's not a single other player in this secondary I think we can expect to be good in 2015 besides Trufant.

3. Earl Thomas, Seattle Seahawks

Gregory Payan/Associated Press

• Is this player actually great?

Earl Thomas is practically already a Hall of Famer. In five seasons, he's been the ball-hawking safety for a Super Bowl champion, gone to the Pro Bowl four years in a row, was named first-team All-Pro three years in a row, and has been the linchpin of a defensive strategy that relies on his amazing ability to cover ground.

• Who else does this team have to absorb the role this player currently fills?

We hear a lot about the Seattle development program as far as finding cornerbacks. Finding safeties? That's a bit different. With Jeron Johnson looking for a starting role in Washington, the Seattle depth chart behind Thomas lists only a couple of undrafted free agents. DeShawn Shead, the nominal backup, has 109 career snaps to his name. And that's before we even get into the idea of replacing Thomas. Just ask Gus Bradley how projecting late-round talent into the Earl Thomas role in this defense works.

• Does the projected absence of this player hurt the passing game or passing defense?

Without a doubt. Other teams have corners somewhat on par with Richard Sherman. Nobody in the NFL has another Earl Thomas.

•  For extra points, is this player essentially the only good player in the section of the unit he currently plays in?

No, because Thomas plays with Richard Sherman and Kam Chancellor. The whole "Legion of Boom" thing -- they're pretty famous, and you may have heard of them. 

That's pretty much the only reason I could think of to keep Thomas at No. 3.

2. Rob Gronkowski, New England Patriots

Elise Amendola/Associated Press

• Is this player actually great?

Rob Gronkowski is not only great, he's uniquely one of a kind. Gronkowski is so amazing that in his first five seasons, he's reeled in 54 touchdowns and caught 459 passes. Only Antonio Gates and Jimmy Graham can even come close to those marks, and they did it by playing in 77 and 78 games, respectively. Compared to Gronk's 65. Gronk is one of the best blocking tight ends in the NFL. Gronk is 16th on the active list for most receiving touchdowns.

He's 26 years old.

• Who else does this team have to absorb the role this player currently fills?

Well, they used to employ Aaron Hernandez. 

But yeah, Michael Hoomanawanui doesn't come close to stretching the defense. The Patriots waived their other receiving tight end, Tim Wright. The Pats would probably respond by running the ball more and hoping Aaron Dobson would be able to step up, which means no, the Pats do not.

• Does the projected absence of this player hurt the passing game or passing defense?

Pretty much every time over the past few years that quarterback Tom Brady has spiraled into a media-determined "decline," it's been because Gronkowski has either not been playing, or been playing hurt. Head coach Bill Belichick drafts wideouts about as well as Adam Sandler writes scripts. You do the math.

•  For extra points, is this player essentially the only good player in the section of the unit he currently plays in?

Tom Brady is a first-ballot Hall of Famer, though he's clearly not the 2007 version of himself at this point. Brandon LaFell and Julian Edelman are passable, perhaps good, wideouts. 

Losing Gronkowski wouldn't make the Patriots a bad offense, but it would remove pretty much all their margin for error on this side of the ball.

1. J.J. Watt, Houston Texans

Patric Schneider/Associated Press

• Is this player actually great?

J.J. Watt is the only NFL player in history with two 20-sack seasons to his name, and he did it playing a third of his snaps as a 3-4 end. He's an aggressive, pesky run defender who guesses right on a lot of his rushes. Over the past three seasons, his cumulative PFF grade is +304.7, and it might as well be a billion. 

Not only is he the best defensive player in the league, he's perhaps the only player in the league worth considering against a franchise quarterback.

• Who else does this team have to absorb the role this player currently fills?

Lessee, the Texans depth at 3-4 end is basically 2014 sixth-rounder Jeoffrey Pagan and 2015 sixth-rounder Christian Covington. I like Covington's chances of becoming a bit of a player, but a bit of a player is about 1/10th of J.J. Watt.

For bonus points: the runner up to Watt for sacks on this team last year was Whitney Mercilus. He had 5.

• Does the projected absence of this player hurt the passing game or passing defense?

The Texans haven't had to play without Watt at all since he was drafted in 2011. It's hard to think of a way that his absence wouldn't crumple this defense and force the Houston offense to throw the ball. Which, over the past two-and-a-half seasons, has tended to end poorly.

•  For extra points, is this player essentially the only good player in the section of the unit he currently plays in?

I would argue that he probably is. 

Vince Wilfork is a Hall of Famer, but he's 33 and hasn't been the same since his Torn Achilles. Brian Cushing hasn't been the same kind of linebacker he was in his early twenties either after back-to-back season-ending surgeries. Jadeveon Clowney is a wildcard -- I expect him to eventually be good, but coming off microfracture and with word that he'll be a close call for training camp? There's probably not much instant impact here. 

There are a number of front seven players here -- including Jared Crick and Benardrick McKinney -- where it wouldn't surprise me to see them have a good year. Watt's the only person I expect to have a good year.