he will never be ****** as long as you take the redshirt off. so i don't think you have anything to lose. its possible the guy will accept it 4th or 5th so i generally keep trying until the season starts, if possible.
ive kept a guy off the depth chart all season and tried him a good 20 or 30 times until the regular season was over, and not gotten it, so i think the chance can be 0%... just depends on the player.