There are times that you might want a player to play all 48 minutes unless he gets injured or fouls out. I wouldn't recommend this, but if you want to do it, the game will let you.
So if I don't have a player listed as a 'Backup' or 'Reserve', he ABSOLUTELY WON'T PLAY? I hope so, because I want a way to guarantee some of these stiffs won't see a minute of floor time, lol.
Friends Do not Let Friends Play 2-3 Zone