I recall a discussion a couple versions back about how changeups fail to develop more than other pitches. Will try to find the thread but anecdotally it does seem that way in my league in 23 at least.
That said, his 2 pitches and other ratings are good enough that he may still be successful as a SP. I would run him out there every 5th day and see what happens before moving him to the pen. Let the kid play!
