I concur with the previous post. This is why I think a smart manager will either have starters with really high Stamina or will have bench players that a coach will play while trying to win the game. Your coach basically has to decide which player will be better, your tired starter or your fresh bench player. If the difference in skills between the two players is too great, then the starter will get extra minutes. I personally think it's better to have depth on your roster as a higher priority than a starting lineup of superstars, otherwise you might end up with a lineup of superstars that are difficult to keep high in Game Shape...
Don't ask what sort of Chunks they are, you probably don't want to know. Blowing Chunks since Season 4!