The List: Nine Minor League Pitcher Breakouts — College Baseball, MLB Draft, Prospects

This week’s edition of The List focuses on pitchers who were not listed in the 2016 Prospect Handbook but whose success—as measured by WHIP, opponent average and strikeouts per nine innings—has placed them squarely on the prospect radar. The question is whether the success is sustainable. The pitchers are listed in alphabetical order.

Chance Adams, rhp, Double-A Trenton (Yankees)
WHIP: 0.97 • AVG: .196 • SO/9: 10.9

A converted reliever from Dallas Baptist, Adams had enough success at high Class A Tampa (5-0, 2.65) that he was promoted to Trenton. The 2015 fifth-rounder worked as a setup reliever in college and as a reliever in his first year as a pro, but he has a chance to have success in the rotation thanks to two above-average pitches in a mid-90s fastball and a slider. He’ll need to develop a changeup to remain in the rotation.

Luis Castillo, rhp, high Class A Jupiter (Marlins)
WHIP: 0.99 • AVG: .227 • SO/9: 6.5

The 23-year-old Dominican has touched 101 mph this season, and his fastball sits 96-97, according to Jupiter pitching coach Jeremy Powell. In addition to the heater, Castillo has a slider with good depth and a power changeup. Though his strikeout rate is below the Florida State League average of 7.8 per nine innings, his stuff and track record portend an upswing.

Yonny Chirinos, rhp, high Class A Charlotte (Rays)
WHIP: 0.95 • AVG: .225 • SO/9: 5.7

Chirinos, a 6-foot-2, 170-pound righthander from Venezuela, signed in 2012. He throws a low-90s two-seamer, a slider in the mid- to upper 80s and a changeup in the mid-80s. His slider has progressed to where it’s now a chase pitch. His fastball sits at 92-94 mph and has touched 95, and he commands it well. While Chirinos’ strikeout rate is below average, his combination of stuff and track record give hope for an uptick in missed bats.

Matt Grimes, rhp, high Class A Frederick (Orioles)
WHIP: 1.06 • AVG: .230 • SO/9: 6.2

A fourth-round pick of the White Sox out of high school in 2010 who did not sign, Grimes fell to 18th round in 2014 after having Tommy John surgery in 2013. Fully healthy, he has seen his velocity tick up to 89-93 mph with good downhill plane. The Georgia Tech product can throw four pitches for strikes and gets good angle on all of his offerings thanks to his 6-foot-5 frame. His relatively low career strikeout rate could portend a future bullpen role.

Matt Hall, lhp, high Class A Lakeland (Tigers)
WHIP: 1.06 • AVG: .202 • SO/9: 9.8

The former Missouri State ace with the killer curveball was a Midwest League all-star thanks to that plus offering. Hall’s fastball touches 90 mph, but he has great pitchability, great mound presence and is a take-your-heart-out competitor. While his fringe velocity might be a red flag as he rises in class, his toughness makes it likely he can succeed against more advanced competition, possibly in a left-on-left role.

Julian Merryweather, rhp, Double-A Akron (Indians)
WHIP: 1.02 • AVG: .210 • SO/9: 8.6

A senior sign for $20,000 out of NAIA Oklahoma Baptist in 2014, Merryweather first drew attention in intrasquad games in spring training with pitches that had Indians teammates muttering the word “nasty.” The 24-year-old commands an interesting three-pitch mix. His fastball ranges 92-95 mph with a good changeup that is about 15 mph slower and an average breaking ball. An athletic pitcher who holds runners well, he does a good job repeating his over-the-top delivery.

Trevor Oaks, rhp, Triple-A Oklahoma City (Dodgers)
WHIP: 1.03 • AVG: .251 • SO/9: 6.1

Oaks spent his freshman year at NAIA Biola (Calif.) before transferring to Cal Baptist, where he emerged as an eligible sophomore and went 11-0, 1.68 with 107 strikeouts and 31 walks in 107 innings. Oaks is a hard worker with top-scale makeup whose stuff has gotten better each year. In college, Oaks was mainly a fastball/curveball pitcher, but he’s now using a slider and a recently added cutter. His velocity has ticked up from college to where he can now touch 93-94 mph. He has been compared to former big league righthander Jon Garland.

Joel Payamps, rhp, high Class A Visalia (Diamondbacks)
WHIP: 0.98 • AVG: .218 • SO/9: 8.1

Payamps signed at age 16 with the Rockies—who had followed him from the time he was 14 years old—in 2010 for $465,000, owing to his advanced feel to pitch. He struggled in the Rockies system, however, and was released in May 2015. He did not pitch last season. Still just 22, Payamps signed with the Diamondbacks in November and has broken out this season. His fastball ranges from 92-95 mph with late life and some arm-side run. His mid-70s slider can get sweepy, and he maintains his arm speed on a firm, mid-80s changeup.

Keegan Yuhl, rhp, Double-A Corpus Christi (Astros)
WHIP: 1.02 • AVG: .222 • SO/9: 7.1

A 35th-round pick from Concordia (Calif.) in 2014, Yuhl succeeds because he can throw all four pitches (fastball, slider, changeup, splitter) for strikes and knows how to locate. His fastball sits 89-92 mph. None of the pitches are plus offerings, but all play up because of his superb command and control. Yuhl’s past track record indicates his strikeout rate could rise.