Pittsburgh Pirates Prospect Mitch Keller Arguably Had One Of The Most Unlucky Debuts In Recent History, But He Could Be The Team’s Ace By The End Of The Upcoming Season.
Last season in Triple-A, Keller pitched to the tune of a 3.56 ERA, 3.60 FIP, and 1.24 WHIP. He walked just 3.0 batters per 9, while striking them out at a 10.7 rate. His ERA ranked 4th in the International League, while he led the league in K/BB%. His HR/9 of 0.79 also led all Triple-A pitchers with at least 100 innings under their belt during 2019.
But based on his brief stint at the MLB level, you wouldn’t have guessed that, at least by his surface numbers. Keller put up a 7.13 ERA, and 1.83 WHIP in his first 48 innings in the Majors. Not too impressive, but I would make the argument that Keller was the team’s most unlucky pitcher in 2019.
For starters, Keller carried over his strong strikeout rate from the minors, even improving it to a 12.2 K/9 ratio. Also, the 23-year-old didn’t have trouble locating the strike zone, indicated by his 3.0 BB/9.
So what about all the hits he gave up? Well many of them were undeserved. No way does his much inflated .475 batting average on balls in play stays where it was last season (just for reference how high that is, Cubs’ lefty Jon Lester had the highest qualified BAbip at .347). Most of the hits Keller gave up were not home runs, indicated by his 1.1 HR/9 last year (MLB average was 1.4).
SIERA and FIP paint a much prettier picture for the top prospect. He put up a 3.78 SIERA and 3.19 FIP during his debut innings. Keller did not give up much hard hit contact either. His 36% hard hit rate is 2% better than league average (38%). Overall in terms of batted ball results, Keller ranks at a nice 69th percentile in exit velocity, and the 59th percentile in hard hit rate, both of which rank him as above average.
Keller also has a decent amount of movement on his pitches, indicated by a 56.9 inches of vertical/9.2 inches of horizontal movement on his curveball, and 35.9 inches of vertical/4.1 inches of horizontal movement on his slider. While his fastball doesn’t have nearly as much movement, it’s spin rate ranks in the 91st percentile of pitchers, so there is room for improvement. Jacob Stallings as his primary catcher should also improve the right hander’s performance. Keller had a 2.6 BB/9, and 12.8 K/9 with Stallings, as opposed to a 10.4 K/9, and 4.2 BB/9 when he was pitching to now ex-Pirate Elias Diaz.
All of this points to a high chance that Mitch Keller will be the team’s ace by the end of 2020. His hiccup of an ERA above 7 has little backing it. Almost every stat points to him having one of the most unlucky debuts in recent seasons. Next season, I could see Keller having an ERA in the low-to-mid 3’s, especially if the Pirates improve their defense.