When the Rockies drafted 6'5 left-handed starting pitcher Jack Wynkoop out of the University of South Carolina in the sixth round of the 2015 draft, Baseball Prospectus's Chris Crawford said that Wynkoop had an outside chance at filling the fifth starter role as soon as 2017. If we can believe the statistics he's been putting up, as well as the promotions he's earned, that looks eminently possible for the 22 year old.
The Rockies assigned Wynkoop to short-season Boise after they drafted him in 2015. There, he tossed 48.2 innings of quality baseball. Wynkoop's 4.25 ERA doesn't stand out, but he struck out 6.3 batters per nine while only walking 1.5. Wynkoop isn't a hard thrower, but a left-handed starter can thrive with a reasonable fastball, at least three usable pitches, and excellent command—see Tyler Anderson.
Thus far in 2016, Wynkoop is going well beyond what he did before. He began the season in Asheville. In 93.1 innings over 14 starts, Wynkoop struck out seven batters per nine innings. He complemented his not bad, Chad Bettis like, strikeout numbers with an even better walk rate: 0.7 per nine. These two figures amount to a K/BB ratio of 10.43. On the strength of them, the Rockies promoted him to Modesto.
Wynkoop made his eleventh start for Modesto last night, and he's been even better there than he was in Asheville. In six innings last night, Wynkoop struck out seven batters in six innings while walking just one. He's struck out 8.4 batters per nine for the Nuts, and he's walked 0.4 per nine. That amounts to a certifiably nutty K/BB ratio of 20. That's 20 strikeouts for every walk.
Setting aside ratios, here are some raw strikeout and walk figures Wynkoop has posted this season. For Asheville, Wynkoop struck out 73 batters and walked seven in 93.2 innings; for Modesto, he's struck out 60 batters and walked three in 64.2 innings. Add it together, and Wynkoop has thrown 158 innings across two levels and has struck out 133 batters and walked ten in 2016.
There have been legitimate questions about Wynkoop's velocity. Scouting reports (see the link above) from when the Rockies drafted him state that his fastball maxes out at about 90 mph, but he usually sits lower than that. It doesn't sound like that has really changed. Those same reports, however, also said that he changes speeds well and has three more usable pitches: a changeup, curveball, and slider. Based on velocity alone, he shouldn't be able to strike out so many batters and walk so few at these levels; however, he's been doing it for long enough to demand attention. If he can continue this in Double-A, which will be a real challenge, then we really might see Wynkoop in the majors in 2017.
No. 4 PuRP Raimel Tapia, 1-5
No. 15 PuRP Tom Murphy, 0-4
No. 16 PuRP Jordan Patterson, 0-4
No. 6 PuRP Ryan McMahon, 0-4, 3 K
Zach Jemiola, 7 IP, 7 H, 2 R, 0 BB, 4 K
No. 13 PuRP Forrest Wall, 2-4, 2 K
No. 14 PuRP Dom Nunez, 1-4, RBI, K
Jack Wynkoop, 6 IP, 6 H, R, BB, 7 K
No. 3 PuRP Brendan Rodgers, 0-4, 2 K
Brian Mundell, 1-4, 2B, 2 K
Garrett Hampson, 0-3, BB, K
Willie Abreu, 1-4, RBI, 2 K
Rookie Grand Junction: Off
DSL Angels 6, DSL Rockies 1 | MiLB.com Box
No. 24 PuRP Daniel Montano, 1-4, 2 K
Triple-A Albuquerque: Not Jeff Hoffman
Double-A Hartford: Sam Howard
High-A Modesto: Ryan Castellani
Low-A Asheville: Drasen Johnson
Short Season-A Boise: Breiling Eusibio
Rookie Grand Junction: Riley Pint
DSL Rockies: TBD