Given how rough and tumble the NFL can be, one of the more intriguing areas of the annual Football Outsiders Almanac is their discussion of team health. They believe that injuries are responsible for 25 percent of the year-to-year change in a team's wins and think sleepers can often be discovered by looking at recent seasons and how injuries have affected the team.
FO ranks teams according to Adjusted Games Lost (AGL) total from 2007-2009. Additionally they provide the 2009 AGL, and and the expected health trend in 2010. The 49ers finished 8th among all teams in AGL from 2007-2009, and was ninth in 2009 alone. FO trends the 49ers as improving, stating that the training staff might have had the best year in the NFL when it came to borderline injuries:
Virtually all of their Adjusted Games Lost came from three traumatic injuries: Nate Clements' fractured shoulder blade, Walt Harris' torn ACL, and Joe Staley's knee sprain. Their other starters missed only four combined games. That number should rise in 2010, but the uncontrollable injury count should decline some, which could see them push up towards the healthiest teams in the league.
The numbers would seem to add up to a healthier year. Of course, it seems fairly difficult to predict major injuries like ACL tores or major broken bones. The Almanac states that the vast majority of players and teams have roughly similar injury projection. I'm guessing that is based on research they've done with player injuries.
Whatever the case, it'd certainly be helpful if the 49ers could stay healthy this year. Little bumps and bruises can be dealt with, but it's the bigger injuries (Joe Staley's in particular) that can be a problem. Of course, even with the Staley injury, we can't forget that Barry Sims filled in quite well for Big Joe. So, even though you'd like to stay healthy, having quality depth is arguably just as important, if not more so.