Jackson Kowar

The Royals will call-up Jackson Kowar to start tomorrow night’s game against the Angels, manager Mike Matheny announced to reporters (including Lynn Worthy of the Kansas City). Jakob Junis will be optioned to Triple-A Omaha in a corresponding move.

Selected with the 33rd overall pick of the 2018 draft (one spot ahead of fellow vaunted Royals rookie Daniel Lynch), Kowar is now regarded as one of the sport’s more promising pitching prospects. Entering this season, Baseball America ranked him as baseball’s #95 overall prospect and the #4 farmhand in the Kansas City organization. Keith Law of the Athletic also placed Kowar fourth in the system, while Eric Longenhagen of FanGraphs slots him eighth. All three outlets credit him with a potentially elite changeup and a mid-90s sinker. Whether Kowar will develop into an efficient strike-thrower figures to determine his ultimate role.

BA projects Kowar as a potential middle of the rotation starter, feeling he’ll develop “at least average control.” Law feels he could settle in at the back of a rotation if his command improves a bit in the coming seasons. Longenhagen, meanwhile, suggests he’s most likely to wind up in high-leverage relief, likening him to former Royal Ryan Madson. Regardless of the exact form it takes, public prospect forecasters all view Kowar as a potential noteworthy part of a pitching staff in some capacity.

Kowar has gotten off to a fantastic start in Omaha this year, his first taste of the minors’ top level. Through six starts, he’s worked to a 0.85 ERA in 31 2/3 frames, striking out a whopping 33.9% of opposing hitters while walking 8.3%. That strong showing has brought his career minor league ERA down to 3.10, slightly better than the 3.53 mark he managed over three seasons at the University of Florida.

He becomes the third of the Royals crop of well-regarded pitching prospects to make his MLB debut. Brady Singer, Kowar’s college teammate, reached the big leagues last season and has thrown 117 2/3 innings of 4.51 ERA/4.20 SIERA ball over his first 23 starts. Lynch was promoted on May 3, although he’s since been optioned back to Triple-A after giving up 15 runs in his first eight innings.

Junis, who moved to the bullpen when Lynch was selected, will head to Omaha to build back up as a starting pitcher, Worthy relays. Junis performed fairly well in the season’s first month while working out of the rotation, although he’s struggled in a relief role. His demotion will open an active roster spot for Kowar, but Kansas City will need to make another transaction before tomorrow’s game. The Royals 40-man roster is full, so a move is necessary to accommodate Kowar’s formal selection.

Even if Kowar sticks in the majors for good, he’ll be controllable through the end of the 2027 season. The early-June timing of his promotion makes it possible he’ll qualify for Super Two status, which would allow him to reach arbitration eligibility for the first time after 2023 (assuming the existing arbitration structure remains in the next collective bargaining agreement). Future optional assignments could change that trajectory.