There's an unknown here that really prevents any of us from commenting on how this should be handled: we have no idea what they think of his ability to hold up under a starter's workload. This is a kid who's only 21, has already had TJS, and had never thrown 45 pro innings in a season before throwing 69 last year. It would be perfectly defensible for the team to doubt his durability as a starter and prefer to keep him in a role where he throws 60-70 high leverage innings a year.
Or maybe they think he can start, and he will be stretched out next spring. Either way, we kind of have to just defer to their determination of the best role for him.