by Danny Tuccitto

Welcome to the second installment of Football Outsiders overview of the injury landscape in 2012. If you missed part one, you can click here to read it. You can also find a brief explanation of Adjusted Games Lost (AGL) at that link or on our glossary page. The main things to understand are that (a) we gather data from injury reports, physically unable to perform lists, and injured reserve lists; (b) injury totals are adjusted based on the participation status of each player heading into each game; and (c) only starters, long-term injury replacements, and important situational reserves are included.

Free agency officially opened today, and there's a ton of information to cover, so let's just dive right into things.

First up, let's split out AGL totals for last season by offense and defense.

Top 8 Bottom 8 Offense AGL Defense AGL Offense AGL Defense AGL HOU 6.7 SF 4.5 PHI 65.2 GB 62.8 BAL 8.1 PHI 8.1 PIT 64.3 DET 58.3 MIN 10.4 STL 8.3 JAC 63.7 DAL 57.5 NO 11.5 CHI 13.6 BUF 51.5 CLE 57.0 SF 11.7 TEN 14.6 ARI 50.3 NYG 56.6 SEA 14.8 SEA 15.0 KC 50.0 CAR 53.0 ATL 17.3 MIA 18.0 TEN 49.9 WAS 48.8 CHI 17.6 MIN 18.5 NE 46.7 BAL 46.4

Over the 11-year span of our injury database, offensive AGL has exhibited the strongest relationship with wins and total DVOA, so it's not a surprise to see six of the eight healthiest offenses in 2012 making the playoffs, while only one of the eight least-healthy offenses did so. In terms of win-loss records, the top eight went an aggregate 84-43-1, while the bottom eight went 45-83. With Chicago missing the playoffs despite going 10-6, really the only two teams that don't fit the pattern are New Orleans and New England. For the Saints, it's a further indictment of their 32nd-ranked defense. For the Patriots, it's further evidence of what we've known for nearly a decade: The only personnel change that seems to cause problems for their offense is when it involves the personnel wearing No. 12.

Although there weren't any teams that had a bottom-eight AGL on both offense and defense, there were four teams that enjoyed top-tier health on both sides of the ball: Minnesota, San Francisco, Seattle, and Chicago. Minnesota is a curious case because you would think the chronic ankle injury that befell recently-departed Percy Harvin would keep them out of the top eight. However, it turns out that Harvin accounted for over half of the Vikings offensive AGL by himself (65.4 percent). The rest of the unit was impeccably healthy (3.6 AGL), including -- amazingly -- Adrian Peterson (0.9 AGL).

San Francisco and Seattle's presence in the top eight of both offense and defense shows that it wasn't just talented defenses and emerging stars at quarterback that helped change everyone's perception of the NFC West; avoiding injuries played a role. I mentioned on Friday that the 49ers have ranked among the healthiest teams for several years running, which their front office will tell you is because they're more into stretching routines than Tony Horton. At the very least, based on what Chief Operating Officer and Grand Poobah of Analytics Paraag Marathe said at the MIT Sloan conference, San Francisco is hyper-focused on preventing injuries. Seattle, on the other hand, hasn't been as fortunate in recent seasons. Their 38.6 AGL improvement on offense in 2012 was the sixth-largest since 2003.

Of course, we can't leave out St. Louis from this discussion of why the NFC West improved in 2012. If you read last year's piece, you might remember that they had a bottom-eight defensive AGL in 2011. Their 35.2 AGL improvement last year ranks as the fourth-best since 2003.

On the flip side, 2012 gave us three of the worst five offensive AGLs and five of the worst 10 defensive AGLs in our database. Philadelphia's offensive AGL ranked as the third-highest since 2002, and their 54.7 AGL increase from 2011 was the largest to date. Meanwhile, Green Bay set a new record for defensive AGL, beating out the 2009 Buffalo Bills (62.1 AGL). The Packers' 37.4 AGL in 2011 means, however, that the defense didn't rank anywhere near the largest year-on-year increase. Maybe they should start stretching more.

Quarterback

Top 8 AGL Bottom 8 AGL BAL 0.0 ARI 8.1 BUF 0.0 JAC 6.2 DAL 0.0 PHI 5.9 NE 0.0 TEN 5.6 NYG 0.0 KC 3.0 SD 0.0 PIT 3.0 SEA 0.0 NYJ 1.6 TB 0.0 CHI 1.5

Eight teams had the good fortune of a clean injury sheet at quarterback this past season, which brings the total since 2000 to 90. Therefore, if we wanted to extrapolate this a bit, we might say the generic odds against your favorite team's quarterback staying off the injury report for the entirety of a given season is about four-to-one.

One thing that's interesting about this table has to do with quarterback AGL having the strongest position-group relationship with offensive DVOA (duh!), team wins, and total DVOA. Although we would reasonably expect none of the teams with bottom-eight quarterback AGLs to have made the playoffs, it's surprising that only three of the teams with pristine quarterback health made the playoffs. In particular, Buffalo going 6-10 with nary a hangnail for Ryan Fitzpatrick probably gave Buddy Nix one more reason to complain about him and -- hot off the presses! -- release him.

On the other side of the ledger, it's pretty clear from Arizona and Kansas City that the recipe steps for a disastrous season are (1) have a sub-par starting quarterback to begin with, and (2) have injuries force even worse backups onto the field.

Running Back

Just so you know, this list includes both tailbacks and fullbacks.

Top 8 AGL Bottom 8 AGL NE 0.0 PIT 25.4 TB 0.0 JAC 22.5 WAS 0.1 GB 17.6 CIN 0.1 NYG 9.2 TEN 0.5 ARI 8.4 DET 0.5 DAL 7.5 SF 0.6 BUF 7.2 HOU 0.7 MIA 7.2

New England and Tampa Bay became the 29th and 30th teams in our database to have zero AGL at the running back position. Obviously, this was more important for the Bucs. For the Patriots, it's true that Brandon Bolden and Shane Vereen battled injuries for several weeks, but their snap counts, both weekly and over the course of the season, weren't enough to consider them "important situational reserves," and Danny Woodhead didn't show up on their injury report until the playoffs.

The backfield situations for Pittsburgh and Jacksonville were almost schadenfreude-worthy at the time. The Steelers didn't need it (because they rely so heavily on Ben Roethlisberger), but the Jaguars really didn't need it (because they rely so heavily on Maurice-Jones Drew). Going back to 2002, Pittsburgh's running back AGL ranked fourth-highest, while Jacksonville's ranked seventh-highest. What's particularly amazing is that, in 2011, these two teams combined for 0.7 running back AGL, so both now rank among the five largest year-to-year increases.

Receiver

This list includes both wide receivers and tight ends.

Top 8 AGL Bottom 8 AGL TB 0.4 NE 29.4 DEN 1.5 NYJ 28.0 HOU 2.1 KC 22.8 CAR 2.4 DET 20.8 ATL 3.8 BUF 20.4 NO 4.2 OAK 19.1 SEA 4.4 IND 19.0 BAL 4.5 WAS 15.2

In the top eight, Seattle had the fourth-largest drop in receiver AGL since 2003, but a division-mate of theirs checked in with the largest drop in our database: St. Louis. The fact that the Rams weren't even in the top eight last season tells you all you need to know about how bad their receiver AGL was in 2011. (In fact, it was 26.4.) Sure, Danny Amendola had another injury plagued season (5.0 AGL), but the rest of the receiving corps stayed relatively injury-free (0.5 AGL).

Reader RickD noted in the comments section of Friday's piece that, given their gamesmanship, the injury reports for the Patriots and Jets aren't all that trustworthy. Where I don't think that applies as much is at receiver. In New England, Rob Gronkowski did legitimately break his forearm, Aaron Hernandez was inactive for six games because of an ankle injury, and Julian Edelman spent about half the season in and out of the lineup with a hand injury before ending up on injured reserve with a broken foot. Likewise for the Jets, Dustin Keller fought his lower body all year, Stephen Hill broke out and then broke down, and Santonio Holmes was shut down in Week 5.

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Offensive Line

Top 8 AGL Bottom 8 AGL MIN 1.1 PHI 42.6 SF 1.2 TEN 36.0 DET 1.9 PIT 31.0 BAL 2.3 CIN 29.8 NO 3.8 ARI 27.4 HOU 3.9 TB 26.3 NYJ 3.9 JAC 24.4 CHI 7.0 BUF 23.9

Not that Eagles fans need another reason for self-loathing, but congratulations, your team had the highest offensive line AGL on record and the largest-ever increase in offensive line AGL. In 2011, only Jason Peters had an AGL above 1.0. In 2012, there were five: Peters (16.0), Jason Kelce (14.0), Todd Herremans (8.0), King Dunlap (2.0), and Danny Watkins (2.0). I don't think it's a stretch to muse that the offensive line injuries played a role in producing the third-worst quarterback AGL this year as well.

Meanwhile, after a 2011 season in which offensive line injuries were the bane of a Bears fan's existence, it's nice (for their sake) to see Chicago among the healthiest eight. Their drop from 22.3 offensive line AGL the prior year represents the 29th-biggest improvement since 2003.

Defensive Line

Top 8 AGL Bottom 8 AGL PIT 0.2 TB 20.3 MIA 0.4 BUF 19.8 NO 2.0 KC 19.8 SF 2.0 CAR 18.7 CIN 2.1 DAL 18.6 PHI 2.2 DET 16.0 MIN 2.9 DEN 15.6 HOU 3.2 WAS 4.5

None of these AGLs are particularly noteworthy from a historical perspective: none rank in the top 10 for single-year totals, and none rank in the top 10 for year-to-year differences. Nevertheless, there are a couple of situations to detail. Tampa Bay's dead-last defensive line AGL is incredible when you put it in the context of the Buccaneers finishing 2012 ranked third in run defense DVOA and having one of the best-ever Adjusted Line Yards for a defensive front seven.

Elsewhere in the table, that "2.0" next to "SF" is noteworthy. First, you'll recall that Justin Smith's biceps injury didn't affect AGL until Week 16, which means the 49ers defensive line AGL was 0.8 until the waning moments of the regular season. Now, add in that their 2012 total comes on the heels of 2.6 AGL in 2011 and 0.5 AGL in 2010. Finally, put all this in the context of a defense that substitutes less than any in the NFL, and you'll see why I keep harping on their lack of depth being unsustainable in the long term.

Linebacker

Top 8 AGL Bottom 8 AGL STL 0.1 GB 40.1 BUF 0.7 CLE 30.1 SF 1.1 BAL 22.9 OAK 1.3 DAL 19.0 DEN 1.4 HOU 17.7 DET 2.0 WAS 16.7 KC 2.4 CIN 15.2 SEA 2.5 CAR 14.4

Rest assured, I realize that a base 3-4 defense will tend to have a lower defensive line AGL and higher linebacker AGL than a base 4-3 defense because of sheer numbers. That applies to San Francisco in the previous section, and also applies to Green Bay in the above table. However, whereas that might be the case in general, the 2012 Packers had the highest linebacker AGL in our database. Furthermore, the difference between their AGL and that of the next-highest base 3-4 (i.e., Baltimore) should preempt any such numbers-related criticisms. Oh, and I should also note that Green Bay's linebacker AGL last season was 29.9 adjusted games higher than it was in 2011, which represents the second-largest increase since 2003.

Defensive Back

Top 8 AGL Bottom 8 AGL STL 0.7 DET 40.3 TEN 0.8 NYG 34.1 SF 1.4 NYJ 25.6 PHI 2.5 OAK 23.9 TB 2.7 DAL 20.0 CHI 4.0 CAR 19.8 DEN 4.4 IND 19.3 CIN 4.9 ATL 19.3

Finally, we come to the defensive backfield. We have the usual healthy suspects like Tampa Bay and San Francisco on one side of the ledger, as well as the team that suffered probably the most high-profile defensive injury in 2012 (i.e., the New York Jets) on the other side. For the second straight year, however, the team I'll close with is the St. Louis Rams.

The 2011 Rams finished with the third-highest defensive back AGL in our database (36.6). One year later, their 0.7 AGL in 2012 ranked as the 23rd-lowest. That year-to-year decrease of 35.9 AGL is easily the largest since 2003, and is nearly half-a-season larger than the previous record-holder, the 2009-2010 Buffalo Bills. This past season, the extent of St. Louis' injuries in their secondary was as follows: 0.5 AGL for Cortland Finnegan, 0.1 AGL for Janoris Jenkins, and 0.1 AGL for Craig Dahl. In 2011, they had six defensive backs with an AGL at least as high as Finnegan's.

As I hinted at on Friday, it isn't a Jeff Fisher effect as much as it is a "throw the bums out" effect. Of the six players that contributed to the Rams' 2011 defensive back AGL, only two, Bradley Fletcher and Darian Stewart, were on their roster in 2012, with neither of them being slated for a meaningful role before the season started. So I guess I should rephrase. There may very well have been a Jeff Fisher effect in St. Louis AGL improvement last season, but all it took was an application of the age-old line that "the most important ability is durability."