The Seattle Mariners recently announced their 2026 coaching staff. The staff experienced relatively little turnover from 2025 to 2026, with only the notable departures of Kristopher Negrón to join the Pittsburgh Pirates staff, Tony Arnerich to the Guardians, and the return of Louis Boyd to player development as assistant director.
2026 Staff Overview
Departures
Negrón had been a longtime part of the Mariners organization, first as a player for part of the 2018 season and then, following his retirement from play in 2019, serving
as an assistant to the director of player development and as manager of the Mariners Triple-A affiliate, the Tacoma Rainiers. He deftly guided the Rainiers to Triple-A West champs in 2021 before being promoted to the big league squad as first base coach in 2022 and then transitioned over to third base coach for the 2024 season. Negrón now takes on a new challenge as the Pittsburgh Pirates’ bench coach, and I don’t doubt we will see that followed by a manager position in the future.
Louis Boyd has moved back into the front office, moving from fielding coordinator to a player development role as an assistant director. The Mariners only committed 69 (nice) errors as a team last year, good enough for the third-best record in the league. The Mariners were also above the AL average for defensive efficiency and overall fielding percentage, but near the bottom of the AL in defensive runs saved above average due largely to dwindling athleticism in the infield.
Tony Arnerich has now accepted a role with the Cleveland Guardians as their new bench coach. Arnerich previously took on the bullpen coach role after Stephen Vogt vacated it in favor of becoming the Guardians’ new manager in 2023. Arnerich has worked in the Mariners organization since 2017, including assistant hitting coordinator and catching coordinator, Minor League field and catching coordinator, hitting coach, and, for the past two seasons, bullpen coach. Arnerich is the second Mariner to depart for Cleveland this offseason and the second to have previously worked with Vogt, as he joins former assistant GM Andy McKay, who also departed this offseason to become the Guardians’ new fielding coordinator.
Among changes to the coaching staff, coaching assistant and replay coordinator Andy Bissell has also left the team to pursue other paths, he announced on Xitter this past November.
Bissell came up big for the Mariners many times over the past seven years, including this challenge of a shift violation by the Royals in the dog days of the regular season. That replay and challenge victory led to the Mariners scoring a much-needed insurance run. Ultimately, this win kicked off an eight-game win streak for the Mariners, including a three-game sweep of the Astros, which would be crucial for putting the Mariners over the top in the division. Can we say for sure that this replay challenge led to the Mariners winning the division? Who can say for sure? But a moment like that, leading to a win, played a huge role going into Seattle’s biggest series of the season.
Additions
To replace the departing Kristopher Negrón, the Mariners bring in Carlos Cardoza as third base coach. This will be Cardoza’s first job on a major league roster, spending the previous 11 years within the Texas Rangers organization, most recently managing their Double-A affiliate, the Frisco RoughRiders. Cardoza managed the RoughRiders to their best record ever in 2024 and received the internal Texas Rangers Bobby Jones Player Development Man of the Year Award following the 2024 season.
The Mariners have also added Jake McKinley as the fielding coordinator to fill in the position after Louis Boyd vacated it. McKinley has most recently served as the head coach at the University of Nevada, leading the school to a Mountain West regular-season championship and earning the Mountain West coach of the year award. I’m sure some of you Wolfpack fans out there are feeling somewhat conflicted at the moment. This won’t be McKinley’s first major league job, but it will be his first on-field job. McKinley previously worked in the Milwaukee Brewers organization, rising to Vice President of Player Development before being hired by the University of Nevada.
A familiar face fills the role of bullpen coach as Austin Nola joins the M’s again. Nola was the centerpiece of the trade that brought Andrés Muñoz, Ty France, Luis Torrens, and Taylor Trammell to Seattle. While all four players have had varying degrees of success for Seattle and Torrens, France, and Trammell have since moved on, there’s no denying that they all played a role in finally bringing about the end of the playoff drought in 2022. This will be Nola’s first coaching position in the Majors, minors, college, or high school. Dan Wilson was serving as Special Assistant for Player Development in 2018 when Nola was signed by the Mariners that November. During his time in Seattle, Nola was lauded for his breakout hitting and for his support of young pitching coming through the Mariners’ system.
Overall, the Mariners and Dan Wilson have kept their staff mostly intact heading into the 2026 season. This will be Wilson’s second full season at the helm for the M’s, so it will be interesting to see how this staff will grow and develop over the course of the season. Though the departures and rearrangements are few, there’s no telling how the waves of any one change might be felt over the course of a year. But you don’t put together a 90-win season by accident. These teams are built through working hand in hand with the staff on the field and the guys in the front office. If they’ve been doing their homework, then ideally they’ve brought in coaches who are bought into the Mariners’ vision and are here to help make our championship dreams a reality.
