I think right now 7 is a pretty good rating for stamina. Stamina also depends on position also. If it is someone who is going to be playing 30-40 plays a game or more you want them to have high stamina. Kickers, punters, they don't seem to be as effected by stamina. However, always good to train stamina because your players won't play well unless they have the energy to perform the plays. They may be the smartest guy and be fast and strong but if they get tired, it will cause your player to not perform as well.