Mitch Keller certainly is an upgrade over two current arms in the rotation, but expectations need to be tempered for the 23-year-old top pitching prospect.
Mitch Keller seems likely to be called up at some point this summer, despite not being called up when the Pittsburgh Pirates saw both Chris Archer and Jameson Taillon head to the Injured List. The club decided to go with Nick Kingham and Steven Brault instead, and despite Brault allowing six runs in 3.2 innings and striking out just two.
The reason being – well the reason stated, as a team can’t admit to service time considerations – is that Keller has added a slider and General Manager Neal Huntington has said,
"“With (Bryan) Reynolds and (Cole) Tucker up here, we’re out of comfort zone enough with guys without a ton of Triple-A experience. The addition of a slider is going to cause us to be a bit more patient, to let him lock this in and utilize it as a weapon.“It would be like bringing a hitter up when he’s in the middle of a mechanical change.”"
Keller hasn’t really pitched to the level of what you’d expect; the 23 year-old does have a 27.6 percent strikeout rate, but also a 3.97 ERA and 11.2 percent walk rate. In his last start, Keller lasted just three innings where he allowed three runs. So maybe he isn’t the most ready, but at some point this summer the Pirates will likely deem he is, but he’s not a projected top of the rotation arm and that’s okay.
When Gerrit Cole got called up in 2013, his report from Jason Parks who now works as the director of professional scouting for the Arizona Diamondbacks, read
"“Elite arm strength; classic power profile; clean/athletic delivery; good mechanics; fastball has elite velocity; works mid-upper 90s; touches triple-digits; explosive offering; slider is easy 7; shows big velocity (upper-80s) and sharp, late tilt; changeup flashes 7 and works easy plus; good deception from fastball; late action to the arm-side; top-of-the-rotation stuff/major-league body; competitor.”"
Cole was projected by Parks with an 8 fastball, 7 slider, and 6+ changeup giving him an overall grade of 7, or a high-end number one. Cole has since gone on and has produced a 3.40 ERA and 3.14 FIP between the Pittsburgh Pirates and the Houston Astros. He was the last projected top flight arm in the Pirates system.
Looking at the last few top pitching prospects in the organization and their future grade from Fangraphs provides an outlook into what to really expect from Keller:
|Pitching Prospect Grades
|*Cole’s Grade from Baseball Prospectus
Jameson Taillon and Tyler Glasnow both made their debut in 2016 with Taillon getting a 55 and Glasnow a 65. In non scouting terms, a 55 is defined as “number 3/4 starters. Approx 3.70 FIP along with about 160 IP” and a 65 as a higher three/lower two with a FIP between 3.00 and 3.30 and near 200 innings. In terms of fWAR, a 55 is around 2.6-3.4 wins and a 65 is around a four-to-five win pitcher.
So far in his career, Taillon has pitched to a 3.67 ERA and 3.54 FIP and has back-to-back 3.0+ WAR seasons; he’s been around a number three starter his career. And that’s fine, a team of Jameson Taillon’s gives you a chance to out and win every night, and while having a 70 or 65 in your rotation is nice, a 55 who ranges up to a 60 isn’t anything to bat your eyes out.
Glasnow, on the other hand, is a different story. He was always high risk because of his control, and in Pittsburgh he posted a 5.79 ERA in 141.1 innings. Before getting hurt this year, however, the big right-hander has a 1.86 ERA and a 4.9 percent walk rate. He, along with Cole, are beginning to pitch like they were projected, and the Pirates have had a problem developing pitchers in the last seven years.
This leads to Keller, a projected 55 middle of the rotation type arm. In their preseason prospect list, Kiley McDaniel and Eric Longenhagen wrote that,
"“We think the slight uptick in Keller’s walk rate last year could just have been caused by an increased focus on changeup usage. His swinging strike rate took a dip when he reached Double-A despite having two clearly plus pitches: an upper-90s sinker and a curveball. It’s possible the two didn’t pair well together and that a better changeup, or a third pitch, will be needed in order to miss bats. Keller’s changeup did improve throughout 2018, but he walked more guys; we think that aspect of his profile will bounce back once development isn’t coloring his pitch usage… He projects as an above-average big leaguer starter who misses an average number of bats.”"
Keller projects as an average starter, an upgrade over Kingham and Brault no question, but he comes in with a projected 4.56 ERA by STEAMER, which is worse than what the other three were projected entering the season of their debut.
The Pittsburgh Pirates top pitching prospect has work to do to become big league ready, and when he does get called up, he projects to be a mid rotation starter and certainly an upgrade to the staff over two guys in there now because of injury. There’s nothing wrong with being a number three starter and he should be able to stay in the league and have a solid career when it’s all said and done. But Keller doesn’t project as the savior Cole, and to an extend Glasnow, was. It’s okay and fine he isn’t, but the expectations that Keller presumably has doesn’t necessarily match what scouts project.