Mariners DFA Jackson Kowar, Create Roster Spot

The Seattle Mariners made a subtle but meaningful roster move, reminding everyone how quickly the back end of a 40-man roster can shift. By designating hard-throwing reliever Jackson Kowar for assignment, Seattle opened a spot to add catcher Jhonny Pereda.

This move reflects both short-term practicality and the kind of long-game roster flexibility teams crave.

Mariners Shuffle 40-Man Roster

Roster management isn’t always about stars. Timing, health, and options matter just as much—maybe more.

The Mariners showed that when they took Jackson Kowar off the 40-man to make room for Jhonny Pereda, whom they picked up from the Minnesota Twins for cash considerations.

Minnesota had just designated Pereda for assignment after signing veteran catcher Victor Caratini to a two-year deal. Seattle, always on the lookout for catching depth, saw a chance to boost their insurance without giving up any prospects.

Why Seattle Needed the Roster Spot

This wasn’t about panic. It’s just smart, proactive planning.

Catching depth rarely holds up for a full 162-game season, so the Mariners wanted an experienced backup beyond their main duo.

The Complicated Career of Jackson Kowar

Jackson Kowar, now 29, has had a bumpy ride. He came into pro ball as a supplemental first-round pick for the Kansas City Royals, carrying high expectations that didn’t quite pan out in the majors.

Over three seasons with the Royals, Kowar gave up 79 runs in only 74 innings. His time in Kansas City ended in the 2023–24 offseason when the Royals traded him to the Atlanta Braves for Kyle Wright.

A String of Trades and Setbacks

Kowar didn’t last long in Atlanta. He was included in the deal that sent outfielder Jarred Kelenic to the Braves, which eventually landed him in Seattle.

His Mariners chapter never really started. During his first Spring Training with Seattle, Kowar tore his UCL and needed Tommy John surgery.

He didn’t get back into games until May 2025, but then a shoulder impingement ended his season early.

Performance and Scouting Snapshot

Kowar pitched just 15 times for the Mariners, allowing eight runs over 17 innings. He struck out 15 and walked seven.

His Triple-A numbers weren’t much better—nine runs (five earned) allowed in 16 innings.

His major-league résumé looks rough:

Stuff vs. Command

Scouts still like Kowar’s raw stuff. His fastball sits around 97 mph, and he’s started throwing more sliders and fewer changeups.

That’s helped him get more swings and misses, but he just can’t seem to find consistent command.

To make things trickier, Kowar is out of minor-league options. Any team that picks him up has to keep him on the Opening Day roster or risk losing him again.

What Jhonny Pereda Brings to Seattle

Kowar’s upside is still more hope than reality. Jhonny Pereda, on the other hand, brings something more concrete: stability.

The 29-year-old Venezuelan catcher has a strong upper-minors track record, hitting .296/.392/.419 in Triple-A.

Pereda’s played in 48 big-league games and has a reputation as a reliable defender with solid game-calling skills.

Depth Behind Raleigh and Knizner

Pereda still has a minor-league option left. That kind of flexibility gives Seattle some useful coverage behind Cal Raleigh and Andrew Knizner.

They don’t have to make a permanent roster move just yet, which is a relief. Sometimes you just want to keep your options open, right?

 
Here is the source article for this story: Mariners Designate Jackson Kowar For Assignment