[Mister_G]

So I just traded for a prospect, thinking I was getting a closer who is almost big-league ready and has great ratings and potential in control, stuff and movement. However, when he showed up in my system on the transactions screen he had been switched to a starter. After clicking on him I realized that I had overlooked the fact that he had a 10 stamina on a 1-10 scale. Problem is, he has a superb cutter and knuckle-curve, but his only other pitch is a changeup which is rated 1 with a 2 potential.

So...my question is whether or not there is a way to develop a new pitch or improve upon his changeup? Can I help this, or is it random? Will putting him in the rotation in AAA help, considering he was being used as a closer? IDK, just let me know. Help appreciated.