yes, tufft, they did say that. Here's patrickm885 on two developer chats:
Does health percentage effect perfomance during the game? Or they just more likely to get hurt? I have never seen a good mlb player only play a 100 games or so just cause he is tired all the time (scwoody - All-Star - 1:46 PM)
It directly impacts the injury rate and also impacts performance. The lower the fatigue level the higher the chance for both consequences. (Nov. 15, 2011)
does age increase the likelihood of injury (independent of its effect on health)? (djbradford - Hall of Famer - 1:38 PM)
No, health rating, fatigue and game situation are what determine injuries. (Jan. 21, 2009)