And yes if you tell the coach no just because you dont like that position you are a spoiled brat, but if you say no because of injury issues than what is there to discuss?
I get you are a brat if you say I will ONLY play position X....but is the 15 year old a brat if he says I would prefer to play ANY of the other 8 positions, please I don't want to pitch.
I'll have to admit that if he were on my team, I'd probably be pressuring him to pitch. I'd try to sell it rather than demand it, but I wouldn't passively take no for an answer. My understanding is that your kid is in a pretty well known program with a lot of talent. They probably won't be so desparate for pitching talent that they will press too much. Trust me, they will press a little, though.