i am thinking each player should have there own fatigue recovery rating
that would make the game more interesting on how often a player is coming out the older they get the lower it drops. this way when playing the game every person who gets tired will miss a different amount of plays before they come back in making the game more strategic you better not give your star rb to many carries so that he is fresh in qtr number 4 when it most matters.
every players energy rating should not be at 100 at the start of games
it should fluctuate if you over use them durring the season then slowly there starting energy rating is lower from week to week and if your team has a bye week then your team as a whole should get a recovery boost
or if you are injured that should effect it as well.