The Seattle Mariners have somewhat surprisingly designated reliever Jackson Kowar for assignment on Tuesday
The Seattle Mariners are making some subtle but intriguing moves this offseason as they continue to tweak their roster ahead of the 2026 season. On Tuesday, the Mariners designated right-handed reliever Jackson Kowar for assignment, a move that caught some fans and analysts by surprise. The decision was made to clear a spot on Seattle’s 40-man roster for newly-acquired catcher Jhonny Pereda, who brings additional depth and experience behind the plate.
Kowar, 29, has had a somewhat turbulent journey since joining the Mariners. Originally acquired in the 2023 trade that sent outfielder Jarred Kelenic to the Atlanta Braves, Kowar was seen as a potential contributor in the Mariners’ bullpen for the coming seasons. At the time of the trade, he was regarded as a reliable arm with MLB experience, capable of slotting into middle relief and providing innings when the rotation needed flexibility. However, injuries and roster shuffling have limited his opportunities in Seattle, and despite flashes of promise, he never fully established himself as a mainstay in the bullpen.
In 2024, Kowar underwent Tommy John surgery, a procedure that sidelined him for the entire season. This was a significant setback for a pitcher who had been steadily working to prove himself at the major league level. The recovery process for such a surgery is notoriously lengthy, often requiring a year or more for pitchers to regain full velocity and control. Kowar returned in 2025, pitching in 15 games and totaling 17 innings, where he posted a 4.24 ERA with 15 strikeouts. While not dominant, these numbers showed that he was serviceable and could be a bullpen option in lower-leverage situations.
Despite this, the Mariners now appear ready to move on, likely due to a combination of roster logistics and strategic planning. Seattle has added other pitching depth this offseason, including the acquisition of Cooper Criswell, and may be looking to give opportunities to younger arms or to shuffle the bullpen to maximize flexibility. By designating Kowar for assignment, the Mariners have removed him from the 40-man roster, meaning that other MLB teams now have the chance to claim him off waivers. If unclaimed, he could still be outrighted to the minors, but his immediate future with the organization is uncertain.
The corresponding move that triggered Kowar’s designation was the addition of catcher Jhonny Pereda, also 29, from the Minnesota Twins in exchange for cash considerations. Pereda has bounced around the league in recent years, with stints at the Miami Marlins, Oakland Athletics, and Minnesota Twins, providing a wealth of experience and versatility behind the plate. While not a star player, Pereda is the type of catcher who can help stabilize a roster and provide depth behind the primary catcher, Cal Raleigh, and backup Andrew Knizner. His arrival gives the Mariners flexibility in managing pitchers and allows Seattle to rest their primary catcher without sacrificing defensive capability.
From a strategic standpoint, Pereda’s acquisition is more than just a depth move. Seattle’s front office has consistently emphasized building a roster that can weather injuries and maintain competitive balance over a long MLB season. Catchers are particularly important in this context because they handle pitching staffs, call games, and help manage workloads. Pereda brings a steady glove, familiarity with pitching mechanics, and an ability to work with younger pitchers—traits that are especially valuable on a team like the Mariners, which features several promising arms in the rotation and bullpen.
While some fans may lament Kowar’s removal from the roster, the move reflects the practical realities of building a 40-man roster. MLB teams must constantly balance positional needs, prospect protection, and veteran experience, and roster spots are always at a premium. Kowar’s departure, while disappointing for those who had been hoping to see him carve out a larger role in Seattle, creates room for Pereda and ensures that the Mariners’ roster remains flexible heading into Spring Training.
Looking at Kowar’s career more broadly, he has proven himself capable at times but has struggled to maintain consistency. After being drafted and rising through the minors, Kowar reached the majors with potential as a middle-relief option. However, injuries, a changing bullpen landscape, and organizational priorities have limited his opportunity to secure a long-term role. That said, his MLB experience and past performance mean he could find a new opportunity with another team. For the Mariners, this is a low-risk move that allows them to focus on the current roster construction and pitching depth.
Pereda’s role on the Mariners is expected to be significant in terms of roster depth and situational usage. While he may not be an everyday starter, his presence allows the team to rest Cal Raleigh and rotate catchers strategically, which can be critical over the grind of a 162-game season. Pereda’s experience with multiple organizations also gives him the ability to adapt quickly to the Mariners’ pitching staff and philosophy, reducing the learning curve and immediately contributing both defensively and in handling pitchers.
From a broader perspective, these moves highlight the Mariners’ approach this offseason: careful roster management combined with targeted acquisitions to fill specific gaps. While fans often focus on big-name signings or blockbuster trades, roster decisions like designating Kowar for assignment and acquiring Pereda are equally important for long-term success. These moves ensure that the team has depth, flexibility, and the ability to adjust as the season unfolds.
In summary, Jackson Kowar has been designated for assignment to make room for Jhonny Pereda, reflecting the Mariners’ strategic emphasis on roster flexibility and depth at key positions. Kowar, recovering from Tommy John surgery and providing moderate contributions in relief, may find a new opportunity elsewhere if claimed off waivers, while Pereda strengthens Seattle’s catching depth and provides immediate value in working with pitchers. These decisions illustrate the balancing act MLB teams face during the offseason, where every roster spot carries strategic importance. As Spring Training approaches, Mariners fans will watch closely to see how these moves impact the team’s performance, particularly in the bullpen and behind the plate.
The Mariners’ 2026 season is still full of potential, and while Kowar’s future is uncertain, the addition of Pereda signals careful planning and a commitment to building a roster capable of competing over a full MLB season. With flexibility, depth, and a mix of veterans and younger talent, Seattle is positioning itself to maintain competitiveness in the American League West while navigating the challenges and uncertainties that inevitably arise in a long season.
