Can the defensive line stay healthy?

The Buccaneers have remade their defensive line but it’s a position that’s been obliterated by injuries in recent years. Just how bad is it, and can 2018 be the year they finally stay healthy?

Based on Football Outsiders’ numbers, in 2016 thirteen players played at least one snap for Tampa on the line (in order of decreasing snaps) - Gerald McCoy, William Gholston, Robert Ayers, Noah Spence, Clinton McDonald, Akeem Spence, Davonte Lambert, Ryan Russell, Howard Jones, Channing Ward, Sealver Siliga, John Hughes III, and Jacquies Smith, who played exactly one before tearing his ACL. Five of them played at least 400 snaps and four played at least 50 percent of snaps but only one played more than 55 percent; McCoy played nearly 800 snaps, or roughly 75 percent of all the Bucs’ defensive snaps. It seems like a lot but is similar to the number Aaron Donald played that year.

In 2017 thirteen players again played at least one snap for Tampa (same descending order with new players italicized) - McCoy, Ayers, McDonald, Russell, Chris Baker, Gholston, Will Clarke, Spence, Siliga, Daryl Tapp, Patrick O’Connor, Jacquies Smith, and Ward. McCoy was again the workhorse, playing over 800 snaps or just over 76 percent. Ayers played 55 percent and the next four played just over 40 percent with Clarke playing 30 percent. Six played over 400 snaps. Stevie Tu’ikolovatu was drafted but didn’t play a down.

How many players are under contract right now for 2018? If you guessed thirteen, you’re wrong! It’s twelve. In order of decreasing salary with new players italicized - McCoy, Jason Pierre-Paul, Gholston, Vinny Curry, Beau Allen, Mitch Unrein, Spence, Tu’ikolovatu, Lambert, Ward, O’Connor, and Clarke.

In 2016 Licht spent 19 percent of the Bucs’ cap space on the defensive line, fourth-most in the league, and their adjusted sack rate was 7.1 percent, 6th best in the NFL. Unfortunately, as we later found out that was an unsustainable rate as they didn’t really cause that much pressure.

In 2017 Licht spent 24.35 percent of the cap, second-most in the league. The adjusted sack rate fell to 4.3 percent, the worst in the NFL and far lower than the average sack rate of 6.7 percent that year. Much closer to their actual [bad] pressure rate.

Right now spotrac.com projects the Bucs’ 2018 defensive line as the third most-expensive in the league, eating up 27.79 percent of the cap, or almost an entire third of the cap taken up by 12 players.

So what does all of this tell us? First, that Licht wants to have lots of functional depth along the line and has been remaking it for a while now. Second, while not using much draft resources on it (a fair criticism) he has nonetheless made it priority; despite a rapidly inflating cap Licht has increasingly dumped an even-higher amount of money into that side of the trenches. 19 percent in 2016 was $29 million dollars and an average of $2.7m per player (12th-most), while 27.29 percent in 2018 equals almost $50 million and more than $4m per player (4th-most). And third, he hasn’t always gotten great returns on those investments. It might also mean the Bucs will sign another defensive line player, whether that’s through the draft or by bringing back Ryan Russell.

But as anyone knows, the best laid plans of mice and men often go awry.

I’m using Football Outsiders’ (FBO) Adjusted Games Lost (AGL). In short, AGL is a simple measurement based on whether or not a player played that week and includes partial games based on whether a player was able to play to their full ability, as calculated from the player’s designation on the team’s injury report that week.

Of the eight offenses to accumulate at least 50.0 AGL [in 2017], none ranked higher than 20th in offensive DVOA, with Cousins’ Washington offense faring the best at 20th despite having the second-most AGL (70.6).

So AGL correlates with a unit’s value over average, though the correlation seems to be stronger for offense than defense, or at least that was the case in 2017. In addition, AGL correlates to games won and lost:

Starting at the bottom of the table, we see that for the 2002-2012 period, the change in AGL from year to year does a better job of explaining why a team won (or lost) more games compared to the previous season than current-year AGL does explaining win totals in the current year. The same goes for the relationship between AGL and DVOA.

Just how bad has the injury luck been for the Bucs along this crucial position?

The defensive line has been dead last or in the bottom three in games lost in four of the last six years. As you can see from the table, the only year the Bucs had good injury luck on defense, in 2013, the offense got annihilated. If you want to know how many AGL the offenses had, simply subtract the Total Defense AGL from the Total AGL. The games McCoy has missed were included because he seems to have a bit of a reputation for being hurt though he’s missed fewer games than many might expect. It’s true he’s played many of them hurt and I’m sure they were added as partial games lost, but the numbers would be even worse if he had sat out entirely.

How do we explain those numbers? To be honest, I’m not entirely sure. Is it the heat? A problem with strength and conditioning? The numbers cross multiple defensive line coaches and staffs. From 2012 to 2017 there were 24 other teams that finished at least once in the bottom-eight of DL AGL. Eleven finished in the bottom-eight just once. Eight finished there twice. Dallas, Denver, and San Francisco finished in the bottom-eight three times. Detroit finished there four times and Washington the most at five times. But it seems when the Bucs lose games from their players they bottom out as the very worst.

And these results may be skewed by gamesmanship of teams looking to trick their opponents, and it’s something FBO noted. They’ve tracked who has played and who hasn’t based on their injury report designation, and in 2014 the Bucs finished second to the Patriots in players listed as questionable and appear to have listed fewer players as probable and more as questionable. Could this have had an effect on the rankings? It appears Koetter may have ended this practice in 2016 (coupled with the simplified injury report rules) as Tampa played 91 percent of the players it listed questionable, the highest in the league, and the number listed as questionable decreased significantly. This held true again in 2017 as Tampa again led the league in playing 93 percent of the players it listed as questionable.

Sometimes the best teams at the end of the season are simply the ones that were lucky enough to stay healthy. The best way to protect your team against bad injury luck is depth, but there’s only so much you can do. Why do you think the Bucs have had such horrific injury luck on the defensive line? Do you think it has to do with a specific factor or is it just random luck due to turn around?