After 7 seasons shaping the Yankees’ catching department, he has moved to Seattle, closing the book on New York. With the Mariners, he has not only secured a new job with a promotion, but also moved back to his roots.

“The Yankees are losing a key member of their coaching staff, Tanner Swanson, who is joining the Mariners as their bench coach,” reported Joel Sherman.

Tanner Swanson is leaving New York behind, and the Seattle Mariners are bringing him home as bench coach under new manager Jason Kanzler. The Mariners hired Jason Kanzler as their new manager on the 4th of November as a replacement for Dan Wilson. The move closes an important Yankees chapter and gives Swanson a broader major league responsibility.

Since 2020, he has served as New York’s director of catching and quality control coordinator on a daily basis. In 2024, the Yankees also named him major league field coordinator, expanding his daily responsibilities. His contract expired after the season, and Seattle offered a role close to his roots.

As Swanson’s reputation grew, so did the Yankees’ framing edge: since 2020, their catchers produced 86 framing runs, the highest in MLB. That figure shows how New York catchers earned called strikes on pitches near zone edges. The team also ranked 11th in blocks above average, showing its gains came through receiving.

Swanson flipped the Yankees’ catching priorities, receiving technique over raw athleticism, and built drills to prove it worked. His influence also reached pitching plans, where he joined the club’s daily preparation and discussions.

One clear contribution was the one-knee-down stance now common across professional baseball today. Rather than keeping knees up, catchers lowered one knee to receive pitches near the bottom. The position helped them present low pitches more cleanly, especially around the strike zone edge. Swanson helped popularize that approach, then built detailed drills around glove movement, setup, and repetition. The idea spread beyond New York, as teams recognized receiving could be taught and improved.

Austin Wells became the strongest example of Swanson reshaping a young catcher’s defensive future there. He introduced organized receiving drills during spring training in 2019 for Twins catchers at major-league camp. Swanson and Aaron Gershenfeld rebuilt Wells’ setup, glove position, and receiving through daily drills together.

By 2025, Wells ranked among baseball’s best receivers, saving 11 to 12 framing runs overall. In 2026, he remained a Gold Glove finalist, showing his improvement had become sustained performance. His progress showed how focused coaching could change a prospect’s defensive reputation over time.

Wells was not alone, as Swanson helped shape a wider group of Yankees catchers throughout. Jose Trevino won the 2022 Gold Glove after leading the league in framing that year. Kyle Higashioka, Luis Torrens, Carlos Narváez, Agustín Ramírez, and Rafael Flores benefited from development work. Swanson’s methods emphasized pitches that catchers handle most, rather than treating every defensive skill equally. He also helped pitchers and catchers prepare together, bringing receiving details into broader game planning.

Replacing Swanson’s daily influence, from Wells’ glove work to pitching-catcher prep, will test whether his methods survive his departure. His departure takes away the coach behind their league-leading 86 catcher framing runs since 2020. Austin Wells’ development also shows how difficult replacing his daily guidance could become. With Aaron Gershenfeld remaining in the catching department, New York has internal experience, but replacing Swanson’s influence across catching development and pitching preparation will not be simple.

Swanson grew up in Washington state, coached locally, and kept family ties and an offseason home near Seattle. Before professional baseball, he coached at local schools and worked with the University of Washington. He later joined Minnesota as catching coordinator before the Yankees hired him in 2019. His family lives near Seattle, and he keeps an offseason home in the area now.

Swanson built his reputation elsewhere, and now returns to the Northwest in a larger role.

How will Swanson help the Mariners?

Seattle’s catcher framing struggles made Tanner Swanson’s hiring one of Jason Kanzler’s most important moves. The Seattle Mariners ranked second-worst in MLB at turning pitches near the edges into called strikes. Only the Angels performed worse, while Cal Raleigh finished 2026 with minus-4 framing runs. Jhonny Pereda recorded minus-2, and Mitch Garver finished minus-4 before retiring after the season. Those numbers exposed a clear weakness, especially when Seattle needed close pitches called strikes.

Swanson arrives after helping the Yankees build baseball’s most productive framing group since 2020. New York catchers produced 86 framing runs during his tenure, the highest total across MLB. The Yankees also ranked 11th in blocks above average, showing gains centered on receiving. That record gives the Mariners a proven example of improving the exact skill it struggled with. Framing cannot fix every pitching problem, but extra strikes can change counts and extend outings.

Swanson’s methods were already taking shape with Minnesota, where he coordinated minor-league catchers for two seasons. He introduced organized receiving drills during spring training in 2019 for Twins catchers at major-league camp. Catchers used resistance bands, weighted balls, and pitching machines to improve their glove movements. Swanson’s Twins work mirrors Seattle’s need; Garver improved under his methods; Raleigh and Pereda now face similar framing deficits

Mitch Garver became a clear example after struggling to frame low pitches in 2018. With Swanson’s one-knee setup, Garver’s called-strike rate climbed from 42% to 48.2% in 2019.

Swanson’s teaching transformed Austin Wells, whose defensive ability remained a major concern initially. Daily work improved Wells’ setup, glove position, and receiving technique significantly. Across 2024–25, Wells ranked third among MLB catchers with 23 framing runs. Jose Trevino also won the 2022 Gold Glove, leading MLB catchers in framing runs that year. Swanson’s influence also reached pitching meetings, connecting catchers’ receiving work with daily game preparation.

He also served as Great Britain’s bench coach during the 2026 World Baseball Classic. His reported appointment therefore addresses Seattle’s weakness with experience built across Minnesota and New York. For Mariners fans, the move offers a coach whose previous work directly matches their needs.