He has Chris Carpenter talent, though different pitchers. One with the nasty 12-6 curve and the other with the sick Juan Guzman in his prime moving fastball, with a wipe out slider. I only mention them together because of the injury histories.
Dustin could pull a Carp, become a terrific reliever or fade away all together. It is really is so up in the air. All that said, there really isn't 25 people on the planet who can pitch as well as a healthy McGowan.