Just play him if he isn't good enough? Cause you learn how to be a better footballer by getting destroyed week in and week out by fitter, stronger, better coached and more polished midfielders... That won't destroy a 17 yr olds confidence will it? He won't become terrified to make a pass because he knows as soon as he stuffs up he isn't good enough to win it back of track the runs and the team loses because of his mistakes....
I love your work Grim. But you learn more on the training pitch than during the game. The game is where you find your weaknesses and then bring them to training to work on.