In terms of results, he definitely has an extremely impressive body of work against what is widely considered to be the best amateur competition out there. I'm not basing my concerns on the results of a few late season starts, especially when he has pitched superlatively in the CWS in years past. I've also only ever seen him pitch in video on line and am not a pitching coach of any repute, but from what I've seen of his motion it just seems like an injury waiting to happen. Granted, that could be said accurately about pretty much every pitcher out there as at some point or another they all experience arm related problems of one severity or another. It seems the best course of action is probably just to leave him alone and see what the results are, both in terms of performance and health, and then re-evaluate after some time.