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10 Mar 2009
by Bill Barnwell
The Dallas Cowboys weren't the only team who had their season dramatically impacted by injuries in 2008. In fact, many of the season's biggest surprises have a fair amount to do with their health -- or lack thereof -- relative to 2007.
Take the Miami Dolphins. The addition of Bill Parcells, Chad Pennington, and about half a full roster of new players had a lot to do with their ten-win improvement upon the 2007 campaign; they were also helped by a shift of over 36 Adjusted Games Lost (henceforth AGL), the largest positive difference in the NFL last year. It wasn't just the shenanigans related to keeping the injury report clean, either: The 2007 Dolphins had 56 instances of a starter missing a game due to injury; the 2008 Dolphins had just 25, and 15 of them were rookie right guard Donald Thomas, who managed all of two quarters before going down for the rest of the season.
Even more impressive were the Atlanta Falcons. Helping the Falcons' resurgence was the fact that they had only one starter -- tackle Sam Baker -- miss time before they clinched a playoff spot. The division-leading Carolina Panthers had the second-fewest AGL in the league, with only 6.7 AGL outside of their offensive line.
The Baltimore Ravens, though, were the trickiest team of all. Unlike the other teams that surged to success, the Ravens were riddled by injury, finishing with the third-most AGL in football with an even 95.0.
For those of you unfamiliar with AGL, it's introduced in an essay called "The Injury Effect" in the back of Pro Football Prospectus 2008. While I won't go into a detailed explanation here, AGL uses the injury report, the status and relevance of a player to his team, and historical data regarding how likely a given player is to play to produce a measure of how dramatically a team is affected by injury. A team's shift in AGL from year-to-year bears a significant correlation with changes in their win-loss record as well as their team DVOA.
These numbers are strictly the figures for starters, those players that replaced them, and players who get significant playing time without starting (think someone like Jonathan Stewart, Adam Terry, or Joselio Hanson). The numbers are not weighted by player quality, although we'll be experimenting with adjusting the numbers for players with Pro Bowl and All-Pro appearances in the offseason.
Going position-by-position, the most- and least-injured teams are mostly who'd you expect:
At quarterback, Kansas City (21.4 AGL) finished just ahead of Detroit, thanks to injuries to both starting quarterback Brodie Croyle and backup Damon Huard, who assumed the starting job for a short period of time. Nine different teams recorded zero AGL on the season.
It's also worth noting that Bill Belichick did not put Matt Cassel on the injury report once all season -- maybe that Tom Brady shoulder injury was serious after all.
As expected, Denver's traumatic set of running back injuries led the league. As players came onto and fell out of the starting role, we ended up with the same figure of 21.4 AGL. If we weighted starters and reserves equally, the Broncos would have ended up with 57 AGL -- no team in the eight years we have data for have had more than 38.4 AGL. The Jets, Dolphins, and Cardinals all made it through an entire year without an injury to their starting halfbacks.
The other set of injuries widely recognized as absurd was that of the Seattle wide receivers (22.9 AGL), which includes injuries to an impressive six different wideouts at one point or another during the season. Our system considers Deion Branch and Bobby Engram to be the expected starters at the beginning of the season, with Ben Obomanu and Nate Burleson being the immediate replacements. When Obomanu went down in the preseason, he was replaced by Logan Payne, who himself only lasted through Week 2. Burleson couldn't make it out of the first week. Once Koren Robinson took over as a starter, we stopped counting Burleson, and the return of Engram got us to stop counting Payne and Obomanu. That's some of the more ridiculous (and subjective) accounting we've ever had to do. Randy Moss and Wes Welker didn't make a single appearance on the injury report, giving New England's the league's healthiest wideouts.
St. Louis led the league in tight end AGL with 12.0, which matches the 12 games Randy McMichael missed with a broken leg.
The most injured offensive line belongs to the Jacksonville Jaguars, who saw long-term injuries to Brad Meester, Maurice Williams, and Vince Manuwai en route to 36.2 AGL. Seattle was right behind with 34 AGL. Naming the healthiest offensive line in football makes me shudder, because it's the Giants and their 0.7 AGL. The starting five of Diehl-Seubert-O'Hara-Snee-McKenzie hasn't missed a single regular season game since the beginning of the 2007 season. That's extremely unlikely to continue in 2008, and as Giants fans saw when Kevin Boothe came into the lineup at the end of the year, it's a scary thought.
Wondering how the Ravens could've been so beat up without being mentioned once? Welcome to the biggest miracle of the 2008 season: The Baltimore defense. They led the league with 32 AGL on the defensive line, with season-long injuries to starters Dwan Edwards and Kelly Gregg. The Cowboys only had two instances all year of a starting defensive lineman even appearing on the injury report, and they were both Probable and played.
18.3 AGL were enough to make San Diego's linebackers the most injured bunch in football, thanks almost totally to Shawne Merriman's knee and the 15 games it kept him out of. Arizona didn't name a single starting linebacker on the injury report all season.
My vote for Ed Reed as defensive player of the year came thanks to what surrounded him in the Baltimore secondary. To review quickly:
Think it was fun being Ed Reed last year? The Ravens ended up with 36.5 AGL in the secondary last year, just barely beating out the Lions' 36.3. There was only a slight difference in performance. The Jets' starters were perfectly healthy, the only team in the league to be as such.
Although we don't count special teams totals in AGL, if we did, the Steelers and Vikings would be tied with 16 AGL each, thanks to Daniel Sepulveda and Heath Farwell, respectively.
The good news is that thanks to the work of Chris Povirk, Devon Teeple, and our newest batch of interns, we'll have even more data to work with in the near future. We're expanding our injury database all the way back to 1996, and we've gathered more information about specific injuries in order to provide more accurate details on how long it takes to heal and the effects they have on players and teams. We're excited to present that information, and we'll be doing so in the coming months.
60 comments, Last at 13 Mar 2009, 3:15pm by Chris