I remember watching a short piece about the job of conditioning the new NFL footballs during the week. I forget what team it was, but basically they get water soaked, scuffed and "conditioned" and then put into practice so that the qb can pick the ones he likes for the coming week. No ball goes into the game from the bench that hasn't been previously touched and approved by the qb. Similar prep in MLB, the balls that are provided to the ump by the home team get "treated."