I've had this problem occur a bunch of times this past season.

Your starters are fine since they lose condition during the game and they need the 5% a the end of the game, but

make sure you train your reserves and subs to 94% or less in condition before the game begins because if they don't play, they can't gain the 5%. I would suggest doing it 30 min before the game since you will probably need to use the 3% and 6% training option.