There have been a handful of dominant performances in the minor leagues this season. Perhaps the most dominant — from any organization, not just Kansas City’s — came on Thursday night from RHP Ethan Bosacker. Bosacker was a 13th-round selection by the Royals in the 2023 MLB Draft. The Xavier product debuted last season with two appearances in the Complex League. His professional career truly got underway to start this season with Low-A Columbia. In 15 starts there, Bosacker compiled a 2.78 ERA across 74.1 innings of work. While he didn’t wow with strikeout stuff (19.6% K%), Bosacker showcased impressive command. He walked just 2.06 batters per nine innings and rarely found himself behind in the count.
Kansas City rewarded Bosacker’s strong start with a midseason promotion to High-A Quad Cities. Since arriving, the results have been even better. In his first five appearances with the River Bandits, Bosacker had pitched to a 1.98 ERA, walking less than two batters per nine innings. The strikeouts haven’t trended upward, but Bosacker’s 13.1% swinging strike rate offers some intrigue that the strikeouts may eventually do just that.
Bosacker flirts with perfection in a dominant outing on Thursday
On Thursday night, Bosacker was the starting pitcher for Quad Cities. Opposite him, starting for Beloit was highly touted prospect Thomas White. The night was a true pitching duel, but Bosacker came out on top in phenomenal fashion. He took a perfect game into the seventh inning. Not only that, he did so with extreme efficiency and dominant strikeout numbers. Bosacker faced 23 batters on the night and struck out 12 of them. It took him just 83 pitches to get through seven innings of work, and only in his final inning of work did he allow a baserunner.
Bosacker finished his night throwing 72.2% of his pitches for strikes. He didn’t walk a batter and finished the day with two hits allowed. The outing drops Bosacker’s season ERA with Quad Cities to an outstanding 1.57. How’d he find so much success on Thursday? The answer lies in Bosacker’s offspeed stuff.
Above, you see the slider. He generated chase with the pitch, including this one that bounced to the plate for a strikeout. Beyond the slider, he also throws a curveball, changeup, and fastball. It’s a full pitch mix that keeps hitters off balance, offering plenty of east-west movement. He also changes the eye level of opposing hitters with that solid fastball that offers good carry up in the strike zone and a curveball that drops off the table. The real star of the night, however, was Bosacker’s impressive changeup. He generates excellent arm-side fading action and hitters simply couldn’t make contact with the pitch.
Without question, Ethan Bosacker has been one of the season’s largest surprises down on the Kansas City farm. He’s 23 years old pitching in High-A, and likely needs a better test to truly gauge how effective he can be long-term. For now, I can only grade a player on the opportunities he’s been given and he’s more than made the most of them. Bosacker has gone — in one season — from a relative afterthought in the system to perhaps one of the most underrated arms it offers. He’s a name you should be watching more closely and just another in a handful of impressive arms developed by the Royals’ current pitching development team.