Pittsburgh's Mitch Keller ranks among the best pitching prospects in the minors right now, along with Michael Kopech (White Sox), Forrest Whitley (Astros), and Walker Buehler (Dodgers), and like Whitley, he was recently promoted to Double-A after dominating in A-ball.
Keller started for the Altoona Curve on Tuesday night against Hartford in the brand-new Dunkin Donuts Park, throwing five solid innings that showed why he's my No. 10 overall prospect but also why he's not going to race to the big leagues any time soon.