I don't think that he has any chronic health conditions. I wouldn't be concerned unless you believe in the notion of "injury prone."
I thought that statheads had proved "injury proneness" to be non-existent along with other non existent myths such as clutch, hot streaks, impact of managerial game moves, importance of line order, lineup protection, the disruptive quality of offensive speed and the importance of any single play within the context of a game.