Any time injuries mount -- especially early in the season -- a popular lament among fans is to bemoan what awful luck their team is having. I have no problem with it whatsoever, because if one is locked in on a favorite team and players keep getting hurt, it's easy to feel like nothing is going right for your boys.
Obviously, this doesn't account for the quality of the player injured, as it's just raw data. For example, the games Matt Kemp missed hurts the Dodgers a lot more than the Padres' loss of Jason Marquis. The Rays' extended stretch without Evan Longoria has been well chronicled as well. Still, the sheer volume of injuries to the teams toward the top is certainly worth mention.
Also, we'd be remiss to write this off only as some sort of franchise misfortune meter. Age matters (ahem, Yankees), as does team conditioning and medical staff. As Fangraphs.com points out, the White Sox are near the bottom of the list almost every season, thanks in part to highly-respected, long-time athletic trainer Herm Schneider.