Keller has struck out 52 batters while walking just three and posting a 1.40 ERA and 0.69 WHIP over 45 innings for Low-A West Virginia.
Yes, those video-game numbers are real, and he's posting them as a 20-year-old in the South Atlantic League, where he's almost two years younger than the average player. After a forearm injury ruined 2015 for him, the big right-hander has taken off like a rocket, adding yet another impressive young arm to the Pirates' embarrassment of pitching riches. Because of that organizational depth, they'll bring him along slowly, but Keller should earn a promotion to High-A soon nonetheless -- he clearly has nothing left to prove at this level.