Mariners lose relief experiment in corresponding move for latest catching addition

The trade with which the Seattle Mariners sent Jarred Kelenic to Atlanta happened barely more than two years ago, yet none of the players involved is entering 2026 with a major league job.

The Mariners saw to that on Tuesday when they designated Jackson Kowar for assignment. They needed the roster spot to accommodate catcher Jhonny Pereda, who had earlier come aboard in a trade with the Minnesota Twins.

If the move is a surprise, it's only because Kowar seemed to have a spot in the Mariners' bullpen in hand with spring training looming. But that was very much a tenuous situation, and the reality is that the team needed a catcher more than it needed a borderline relief arm.

Mariners end experiment on Jackson Kowar after trade for Jhonny Pereda

It was in December of 2023 that the Mariners acquired Kowar alongside fellow righty Cole Phillips in a trade with the Braves. Kelenic was the headliner going the other way, with Marco Gonzales and Evan White going with him to provide Seattle with salary relief.

Though that salary relief was the main point of the trade for the Mariners, Kowar and Phillips brought some upside as live-armed pitchers with some projectability. For his part, Kowar was a first-round pick in 2018 who had been rated as a top-100 prospect in 2020 and 2021.

His Mariners tenure unfortunately took a turn for the worse just months later, as he needed to undergo Tommy John surgery in March of 2024. That cost him the entire season and delayed his Mariners debut to May 28 of 2025.

Kowar did flash a 97.3 mph fastball in 15 relief appearances as a Mariner, but that kind of velocity is increasingly ordinary for a relief pitcher. It didn't keep him from being knocked around, as he struck out 15 and gave up four home runs in 17.0 total innings.

The 29-year-old will almost certainly catch on somewhere, but whatever hype he once had as a prospect is now long dead. Unless he can add more velo to his fastball or unlock another pitch, he's going to keep straddling that line between the majors and Triple-A.

In any case, this closes the book on one of the sadder trades the Mariners have ever made.

Phillips still hasn't thrown a pitch in the pros since being drafted in 2022. Gonzales and White are out of organized baseball. And just five years after he was one of baseball's elite prospects, Kelenic has been reduced to accepting a minor league deal from the Chicago White Sox.