40 in 40: Jackson Kowar has a second act in Seattle

The former frontline starter-turned-reliever has landed in a good place to try to straighten out a flagging pro career

Jackson Kowar comes to the Mariners as a result of not one but two cost-saving moves: first, Atlanta sold low on former rotation stalwart Kyle Wright, trading him to Kansas City rather than paying the righty, currently rehabbing from shoulder surgery, for a year of nothing. Then, Atlanta flipped Kowar to the Mariners as part of the Jarred Kelenic/salary-dump trade of Marco Gonzales and Evan White. All of this is an annoyingly high price for the type of player who regularly appears on waivers in the leadup to spring training, but for the moment, let’s set aside the sting of losing Kelenic and agita about the team’s finances and instead focus on the perils but undeniable promise of Jackson Kowar.

The Royals had a bonanza of top picks in the 2018 draft and used the first five of them on college pitching: instant rotation, just add water. The Royals tapped Brady Singer from the University of Florida with their first pick (18th overall); 15 picks later, they took Singer’s rotation-mate Kowar, the Gators’ Saturday starter to Singer’s Friday night starter, but realistically, the 1B to Singer’s 1A. Both look poised to make quick ascents to the Royals’ rotation and carry forward their college success.

But real life, as it so often does, intervened to spoil this successful approach on paper. Singer progressed steadily through the minors, debuting in the pandemic-shortened 2020 season, but has been hampered with shoulder and back injuries. Kowar, on the other hand, found difficulties in commanding his stuff at the next level, finding himself somewhat susceptible to the long ball. After being elevated to MLB in 2021, Kowar has mightily struggled to command the zone, leading to some eye-wateringly poor big-league numbers that don’t seem appropriate for a 21st rounder let alone a first-rounder.

However, there are some reasons to bet on a Kowar bounceback in Mariners blue, beyond even the track record of success the organization has with re-igniting the careers of soft-tosser reliever castoffs. Firstly, while Kowar banked a pile of struggles, he was far from the only Royals pitcher to do so. There’s a saying in teaching: when one student fails a test, that’s on the student; when the entire class fails, that’s on the teacher. In 2022, our sister site Royals Review posted a lengthy article about the failures of the Royals pitching development, with former pitching coach Cal Eldred firmly in the crosshairs. You knew the Royals pitching was bad, but were you aware of how bad?

Happily, things have gotten better with a new regime over in Kauffman Stadium, and the Royals are currently enjoying the breakout success of Cole Ragans, a pitcher the Rangers couldn’t unlock the potential of (and for that, we salute the Royals). But that change might have come too late for Kowar and his ilk.

Kowar came to the Royals throwing a fastball, changeup, slider and curveball, with the fastball well-regarded for his ability to both run and sink it, almost like a two-seamer, and the changeup as his consensus best whiff-getting pitch, with the slider and curveball lagging well behind but the latter projected as an eventual league-average pitch. The Royals had Kowar scrap the curveball, a pitch he worked on extensively at the alternate site, at the big-league level, but simplifying his arsenal didn’t produce better results for the righty; nor did a move to the bullpen in 2022 despite an increased strikeout rate.

Kowar’s fastball did tick up in the bullpen, from 93-95 on average to 96-97 on average, but he continues to struggle with commanding the pitch; at times it gets good riding action and induces ugly whiffs at hitters’ eyes, and other times he throws it non-competitively, well above, outside, or in the dirt. That can lead to walks, which means his misses that leak into the heart of the zone to be damaged become extra-damaging, such as in a game against the Astros in late September where he walked Alex Bregman, gave up a single to José Abreu, and then surrendered a three-run home run to Chas McCormick. In watching his misses below the zone, it almost feels like Kowar gets over the top of the ball too much, firing darts into the dirt, easy takes for MLB-caliber hitters. Kowar has always drawn praise for his easy, repeatable mechanics, but perhaps some elements of those mechanics don’t bear repeating.

But that’s not the only issue the Mariners pitching development staff will have to solve with Kowar; they’ll also have to suss out why Kowar’s changeup, his bread-and-butter pitch during college that scouts hung a 60 grade on, has been so hittable at the next level. An average changeup should earn a whiff about 30% of the time; Kowar’s supposedly above-average changeup was well below that last season, at 25.5%. Here’s what Kowar’s high-spin changeup looks like at its best, when it has late sink and almost screwball movement:

But too often, hitters have looked comfortable against the pitch. Here’s Mauricio Dubón, not exactly a fearsome power hitter, doubling off a changeup that arrived looking like a bad slider. Too often, Kowar isn’t able to consistently get the pitch to move and sink away from batters, and it winds up in a hittable place.

There’s also a question of how well Kowar’s fastball—which is at its best, swing-and-miss wise, when he’s riding it up above bats—will tunnel with a pitch that needs to live in the bottom of the zone. Being able to throw the fastball consistently for a strike low in the zone would go a long way with helping those two pitches co-exist, as will continuing to develop a tight, gyro-spin slider that was actually his best whiff-getter last year.

It’s early in his career to call Kowar a reclamation project, but it’s undeniable that his results haven’t matched his draft pedigree. The pitch characteristics are there: when Kowar looks good, he looks unhittable between the high-velocity fastball that bears in on hitters and the Bugs Bunny-adjacent changeup. The challenge for the Mariners pitching development staff will be in getting that best version of Kowar to show up consistently, and it’s a sizable one. But Kowar is still just 27, and his second act begins now.