After missing most of 2015 with a forearm strain, the Pirates’ 2014 second-round pick has been a revelation this spring in his first taste of full-season ball, logging 67 innings over 12 starts thus far, and punching out 76 batters while walking just seven. Additionally, Keller has held opposing bats to a paltry .196 BAA, and allowed just three home runs over 252 plate appearances. His first-half performance earned him the starting nod in the Sally League All-Star Game last week, where the impressive righty breezed through his inning of work.

Keller needed just 11 pitches – all fastballs and curveballs – to retire the South Division All-Star’s 1-2-3 batters. The heater sat comfortably in the low 90s with good downward plane on the pitch and resided mostly at the knees. The curveball has evolved from the nascent 12-to-6 breaker he threw in high school to a hard-biting 11-to-5 hammer that plays as both a freeze offering and a bury pitch when ahead in the count. Both of his strikeouts in the All-Star Game were recorded on breaking balls – the first coming on a plus bender in the zone swung through by the Braves’Ray-Patrick Didder, and the second a knee-buckler, following an elevated fastball, that sent the Rockies’ Brian Mundell (then league leader in batting average) back to the bench with a backwards-K. The two strikeouts bookended a soft chopper off the bat of the Mets’ Vinny Siena.

Keller turned just 20 years old in April, and while his 2016 results have been spectacular thus far, the Pirates have the luxury of allowing him further time in the Sally League to improve his off-speed stuff as well as the consistency of his finish across his entire arsenal. It’s a low-maintenance delivery with solid pacing, but he can slip into a non-uniform stride from time-to-time and when he gets too short out in front he has a tendency to yank his pitches to the glove side. The upside is that of a solid mid-rotation arm and, provided he finishes out the season in even remotely the style he’s started, Keller should be firmly entrenched on the national prospecting scene moving forward.