As a HS coach here is my opinion, if in fact this is the whole story. In no way shape or form do you do that. This is a move that is done prior to the kid ever leaving the dug out. In my opinion you do not pinch hit unless you get the pinch hitter in the on deck circle to warm up properly and to save the player from embarrassment. This is a move that needs to be explained to the kid. This players are still children and have emotions that at time they can not control, both physically and mentally. You are in a situation where you need a child to continue to play in an important game and they need to know that you made the change for a valid reason and you still trust them.