I change my manager settings like said above. I take my ML'ers off the the Def rep and player rest list and replace them with prospects. Also, I manually change all my pitchers to throw 5-20 pitches depending on their stamina, to go along with tandems set at 40 pitches. I've had over 40 players play several times. It's crucial to have your prospects develop and spring training playing time is a good way to start their season. I don't worry much about my veterans playing in ST.