NEW YORK — Tanner Swanson is leaving the Yankees to become the Seattle Mariners’ bench coach, ending seven seasons on Aaron Boone’s staff and creating a vacancy in the operation that helped turn New York into baseball’s leading pitch-framing team.
Swanson, 44, is joining new Seattle manager Jason Kanzler after serving as the Yankees’ director of catching since 2020 and major league field coordinator since 2024. The move gives him a promotion after his responsibilities in New York expanded from instruction behind the plate to wider game preparation.
The departure also creates an uncomfortable contrast for a Yankees organization sticking with general manager Brian Cashman and Boone after another Division Series elimination. New York has maintained continuity in its senior baseball positions while another club lured away one of its key pillars.
Seattle offers promotion Swanson did not have in New York
Swanson joined the Yankees ahead of the 2020 season after two years as the Minnesota Twins’ minor league catching coordinator. His original assignment was centered on catchers, but the Yankees expanded his duties and reach in 2024 as his work gained recognition.
As field coordinator, he worked close to Boone and the major league staff on preparation and strategy, including the pitching side of the game. His broader role provided the foundation for a move into the seat beside a manager.
Seattle had an opening after parting with Manny Acta during a coaching overhaul. Kanzler, a first-time big league manager, will add Swanson as his bench coach, a role with direct involvement in daily preparation and decisions during games.
Swanson also worked as Great Britain’s bench coach during the 2026 World Baseball Classic. His contract with the Yankees was expiring, and other clubs had shown interest in him previously.
Yankees lose a measurable defensive advantage
The most striking evidence of Swanson’s influence is New York’s performance in catcher framing, the skill of receiving borderline pitches in ways that increase the chance of a called strike.
From 2020 through 2026, Yankees catchers produced 86 catcher framing runs, the most in MLB, according to Statcast figures published by MLB.com. The Yankees ranked 11th in blocks above average over that span.
Those totals show both the scale and the limits of the Yankees’ edge. Pitch presentation became an exceptional strength, while blocking graded much closer to the middle of the league. Framing runs reflect extra value from converting borderline pitches into called strikes, not an overall ranking of every catching skill.
The Yankees’ own 2026 coaching announcement documented an earlier stretch of success. From 2020 through 2025, their catchers had 73 framing runs, ranked second in the majors in shadow strike rate at 48.6% and third in defensive runs saved with 39.
Jose Trevino won the American League Gold Glove and Platinum Glove awards in 2022. Austin Wells later developed into a Gold Glove finalist, while J.C. Escarra gave the club another catcher who advanced through its development system.
The Yankees traded Trevino to Cincinnati for reliever Fernando Cruz, moved Carlos Narvaez to Boston for pitching prospect Elmer Rodriguez and included Kyle Higashioka in the trade for Juan Soto. Swanson worked with run prevention and catching development coordinator Aaron Gershenfeld as the organization built that depth.
Seattle identifies an immediate use for Swanson’s specialty
The Mariners have a practical reason to prize Swanson’s expertise. Seattle struggled with converting borderline pitches into strikes during 2026, ranking near the bottom of the majors in that area.
Statcast credited Seattle catcher Cal Raleigh with minus-4 framing runs in 2026 and Jhonny Pereda with minus-2. Those figures contrast sharply with the Yankees’ long-term receiving results under Swanson.
Swanson returns to his home state after growing up in Washington and playing at Central Washington University. His hiring gives Kanzler a coach who knows the division rival Yankees’ preparation process and has already carried responsibilities beyond catching instruction.
For New York, the position remains unfilled as of Nov. 7. The Yankees must find a new lead voice for their major league catching operation while deciding how to replace Swanson’s responsibilities alongside Boone and the pitching staff.
Swanson’s exit exposes a flaw in Cashman-Boone leadership
The Swanson move arrives in the same week that former Triple-A manager Shelley Duncan left for a job with the rival Boston Red Sox. The two positions are different, but the exits remove experienced personnel from a Yankees development structure Cashman has overseen.
His group helped the Yankees lead the major leagues in catcher framing runs during that span, giving its pitching staff an edge on borderline pitches. He developed a group of catchers valuable enough to play important roles in the Bronx or become pieces in major trades.
Cashman remains in charge of baseball operations and Boone is returning as manager for 2027 despite the Yankees’ latest Division Series loss. Brad Ausmus, the former big league manager, continued as bench coach. Seattle, meanwhile, had the position and authority to make Swanson a direct deputy to its manager. The difference between the two clubs was not Swanson’s record, but the organizational push for change.
The Yankees showed that internal advancement was possible when they elevated Jake Hirst to assistant hitting coach for 2026 after he attracted outside interest.
The result puts a concrete staffing problem on Cashman and Boone’s desk. Losing that institutional knowledge is the immediate price of the Yankees’ continuity-first approach.
The Yankees had another specialist involved in that process, player development catching coordinator Aaron Gershenfeld, who is likely to fill in.
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