Offseason In Review: Seattle Mariners

The 2025 Mariners were a game away from the World Series. Their two-decade playoff drought and status as perennial runner-up increasingly feels like a thing of the past. They enter the 2026 season as the AL West favorite in projections at both FanGraphs and Baseball Prospectus after a winter that featured multiple upgrades.

Major League Free Agent Signings

• Josh Naylor, 1B: Five years, $92.5MM
• Rob Refsnyder, OF: One year, $6.25MM
• Andrew Knizner, C: One year, $1MM

Option Decisions

• Team declined $12MM mutual option on C Mitch Garver (paid $1MM buyout)
• Team exercised $7MM club option on RHP Andres Munoz
• INF Jorge Polanco declined $8MM player option

Trades and Waiver Claims

• Acquired INF/OF Brendan Donovan from Cardinals in three-team trade also involving Rays; Mariners sent SHP Jurrangelo Cijntje, OF Tai Peete, Competitive Balance pick (Round B) to Cardinals, 3B Ben Williamson to Rays
• Acquired LHP Jose A. Ferrer from Nationals in exchange for C Harry Ford, minor league RHP Isaac Lyon
• Acquired RHP Yosver Zulueta from Reds in exchange for minor league RHP Dusty Revis
• Acquired minor league LHP Robinson Ortiz from Dodgers in exchange for minor league RHP Tyler Gough
• Acquired minor league RHP Alex Hoppe from Red Sox in exchange for minor league C Luke Heyman
• Acquired RHP Cooper Criswell from Mets for cash
• Acquired C Jhonny Pereda from Twins for cash
• Acquired LHP Josh Simpson from Marlins for cash
• Acquired RHP Cole Wilcox from Rays for cash
• Claimed RHP Ryan Loutos off waivers from Nationals

Extensions

• None yet

Notable Minor League Signings

• Mitch Garver, Dane Dunning, Connor Joe, Casey Lawrence, Randy Dobnak, Guillo Zuñiga, Patrick Wisdom, Michael Rucker, Jhonathan Diaz, Brian O’Keefe, Jakson Reetz, Will Wilson, Brennen Davis

Notable Losses

• Eugenio Suarez, Ben Williamson, Harry Ford, Caleb Ferguson, Luke Jackson, Tayler Saucedo (non-tendered), Gregory Santos (non-tendered), Trent Thornton (non-tendered), Jackson Kowar (claimed by Twins)

When fans think of the Mariners, the dominant starting rotation is often the first thing that comes to mind. The 2025 season, Seattle’s best since 2000-02, played out in somewhat uncharacteristic fashion, however. The rotation was solid but not elite. Mariners starters barely cracked the top half of baseball in terms of ERA, due in part to injuries up and down the staff. Seattle’s bullpen ranked top-10 in ERA, however, and the lineup finished tenth or better in runs scored, home runs, on-base percentage, slugging percentage and wRC+. Cal Raleigh, the AL MVP runner-up, played a huge role in the Mariners’ offensive eruption, but the Seattle lineup was a strong unit top to bottom.

Seattle’s deadline acquisition of Josh Naylor from the D-backs played a big part in that. Naylor hit the ground running in the Emerald City and immediately looked at home, slashing .299/.341/.490 with nine homers in 210 plate appearances. The 5’10”, 235-pound Naylor even delighted baseball fans (not just Seattle fans) by somehow going 19-for-19 in stolen base attempts despite sitting in the third percentile of big leaguers in terms of average sprint speed, per Statcast. Naylor entered the season with 25 career steals in 598 games. He played 54 games as a Mariner.

President of baseball operations Jerry Dipoto made it known before season’s end that keeping Naylor was not just a priority for the Mariners but the offseason priority. Appearing on the MLB Trade Rumors podcast, Dipoto told host Darragh McDonald that Naylor was “as good as anybody that’s played in the last handful of years at hitting in this ballpark” while voicing a strong desire to keep the 28-year-old slugger.

True to his word, Dipoto wasted little time in making an aggressive push to keep his newly acquired first baseman. Naylor, who also raved late in the season about how much he loved playing in Seattle, was one of the first major free agents off the board, coming to terms on a five-year, $92.5MM deal two weeks after the World Series wrapped up.

Naylor’s deal is the largest contract the Mariners have given to a free-agent position player since Dipoto began running baseball operations for the Mariners more than a decade ago — and not just barely, but by a magnitude of nearly four times. Dipoto has been open about his desires to avoid building a roster through free agency, and his affinity for working the trade market is well known. That Naylor nearly quadrupled the $24MM guarantee paid to Mitch Garver underscores how strongly the Mariners felt about keeping him. Prior to the Naylor signing, Garver was the only free agent position player to sign a multi-year free agent deal with Seattle in ten years.

While Naylor was the priority, the Mariners remained open to re-signing veterans Jorge Polanco and Eugenio Suarez, both of whom hit in the middle of the lineup down the stretch and into the playoffs. Polanco was always deemed more likely, but the Mariners apparently balked at matching or topping the two-year, $40MM deal he received from the Mets. That $20MM average annual value was steeper than nearly any pundit or fan thought Polanco would command.

The veteran Polanco’s departure left the Mariners in a familiar position. As was the case the offseason prior, the M’s had openings at both second base and third base. Dipoto and GM Justin Hollander spent most of the 2024-25 offseason working the trade market to find an option at one or both positions before ultimately re-signing Polanco to one-year deal that turned out to be a raucous bargain.

For much of the current offseason, it looked as though things might play out similarly. The Mariners engaged with the Cardinals on Brendan Donovan early, but interest in the utilityman extraordinaire was robust. Dipoto and Hollander kept in touch with Suarez’s camp, were at least loosely involved in the market for star NPB third baseman Kazuma Okamoto, spoke to the D-backs repeatedly about Ketel Marte and inquired on the Cubs’ Nico Hoerner. There were surely other trade and free agent targets whose names didn’t become public.

Through it all, the Mariners were cited as one of the top suitors and front-runners for Donovan, who entered the offseason as a veritable lock to be traded by the rebuilding Cardinals. It may have taken longer than fans hoped, but the Mariners eventually got their man on Feb. 2, parting with top pitching prospect Jurrangelo Cijntje, outfield prospect Tai Peete, young third baseman Ben Williamson and a Round B Competitive Balance draft pick (No. 68 overall) in a three-team deal that brought Donovan their way. Seattle’s interest in the former Gold Glove winner dated back to last season, meaning the three-team swap capped off more than a yearlong pursuit of the versatile infielder/outfielder.

Donovan indeed feels like a perfect fit for the M’s. He’s a quality defender at either third base or second base, meaning the Mariners can see which of Cole Young and Colt Emerson stand out the most this spring. The hope is that Emerson is the team’s long-term third baseman — or perhaps shortstop, if J.P. Crawford departs in free agency next winter — and that Young is the second baseman of the future. Donovan’s ability to play either spot lets the Mariners take a flexible approach to their infield alignment. And if both players eventually force their way onto the roster, Donovan can split time between those two positions, the outfield corners and designated hitter.

While Seattle paid a steep price to acquire Donovan in terms of the talent they surrendered, they’re getting him for just $5.8MM this season and can control him through the 2027 campaign. It wouldn’t be a surprise if the two parties eventually talked extension. Donovan was open to a long-term deal in St. Louis even as the Cards embarked on a rebuild.

Time will tell whether he feels similarly about his new surroundings, but at the very least he doesn’t appear to be dead-set on testing free agency 18 months from now. Recent extensions for Tommy Edman and Ryan McMahon paid that pair of comparably aged infielders $70MM total; Donovan might command a bit more, but a five-year deal in that general range (beginning with next year’s final arbitration season) feels like something that could work for both sides, speculatively speaking.

Even if no extension comes to fruition, Donovan will be hitting at or near the top of a deep Mariners lineup for the next two seasons. He’s the sort of versatile, high-contact bat the Mariners coveted several years ago when trying to reshape their offensive identity after years of ranking at or near the top of the league in strikeouts. With Donovan (career 13.5% strikeout rate) and Naylor (career 16%) now helping to anchor the lineup, the M’s have a bit of a different feel than the all-or-nothing bunch to which we’d grown accustomed earlier this decade.

The Donovan trade may have been the Mariners “signature” trade of the offseason, but it wasn’t the only swap of consequence for Dipoto, Hollander & Co. One of the Mariners’ first moves post-Naylor was to address the lack of reliable left-handed relief in their bullpen, swinging a trade for Nationals southpaw Jose A. Ferrer. Many fans were shocked to see the Mariners part with top catching prospect Harry Ford to acquire a reliever, but Ford was blocked by Raleigh with no clear path to playing time in Seattle. That doesn’t mean he can be swapped out for any old bullpen arm, but what Ferrer lacks in name recognition he makes up for in extremely intriguing underlying numbers.

Ferrer’s 4.15 ERA over the past two seasons (4.48 in 2025) isn’t going to garner much attention. However, that mark came playing in front of a porous Nationals defense that rarely did the flamethrowing sinker specialist help. The 25-year-old Ferrer (26 next week) averages a blazing 97.7 mph on a sinker that’s helped him post a gargantuan 61% ground-ball rate dating back to 2024 — fifth highest in all of baseball (min. 100 innings pitched).

In 2025, Ferrer upped his strikeout rate from the prior year’s 19.4% to a nearly league-average 21.9%. His swinging-strike rate rose to a slightly above-average 11.5%. Ferrer has only walked 4.9% of his opponents the past two seasons. That blend of plus command and plus-plus ground-ball tendencies, coupled with even average bat-missing abilities (and a competent defense behind him) gives Ferrer immense breakout potential. Metrics like SIERA (2.97) and FIP (2.95) already feel he’s great, and the Mariners’ track record in coaxing breakouts from unheralded relievers (e.g. Paul Sewald, Gabe Speier, Drew Steckenrider, Justin Topa) shouldn’t be overlooked. Ferrer is controlled for four more seasons and has two minor league option years remaining. Adding him to a bullpen anchored by Andres Munoz and Matt Brash could make for a lethal trio.

Most of the remaining moves were more on the margins of the roster. Rob Refsnyder and his lifetime .281/.383/.443 line against lefties (.302/.399/.560 in 2025) gives manager Dan Wilson a big platoon bat to pair with lefty-swinging outfielder/designated hitter Dominic Canzone, who’s coming off a breakout .281/.358/.481 showing in 268 plate appearances. Canzone more than held his own against lefties, so he’ll still get some left-on-left looks, but all of his power was against righties. Only two of his 22 extra-base hits (one double, one homer) came versus southpaws.

Andrew Knizner was brought in on a moderately surprising big league deal to be the backup to Raleigh. He’s earning just $1MM, so it’s a minimal commitment if Knizner doesn’t pan out. He’s a career .211/.281/.316 hitter whose defensive marks have improved in a small sample over the past two seasons. Notably, he was one of the best catchers in Triple-A last year when it came to challenging pitches under the incoming ABS system, which could have factored into the decision. Catching depth in general was a priority though, as they also reunited with Mitch Garver on a minor league deal and picked up Jhonny Pereda from the Twins in a cash swap.

Assembling a deep collection of optionable arms also proved to be a priority this winter. The Mariners acquired a whopping six optionable young relievers via either small trades or waivers. The current big league bullpen doesn’t have much flexibility — Ferrer and Brash are the only optionable arms, and neither is being sent down anytime soon — so it’s possible something will shake loose later in camp with the Mariners moving on from an out of options arm like Casey Legumina. The Mariners added Yosver Zulueta, Josh Simpson, Cole Wilcox, Alex Hoppe and Robinson Ortiz via trade and claimed Ryan Loutos off waivers. They’ll have plenty of options to evaluate when injuries inevitably crop up among the more experienced members of the bullpen.

The starting pitching lacks that same level of depth, particularly after sixth starter Logan Evans suffered a UCL tear that’ll require season-ending surgery. The Mariners’ top quintet of Logan Gilbert, Bryan Woo, George Kirby, Luis Castillo and Bryce Miller is among the most talented in the game, but the top options behind him are now out-of-options swingman Cooper Criswell, former prospect Emerson Hancock (who’s struggled in the majors thus far) and non-roster veteran Dane Dunning. Finding an optionable rotation candidate or bringing in one more low-cost or non-roster veteran would arguably still be prudent, but even if they opt to do so, it’s not likely to be one of the top names available.

By and large, the Mariners’ heavy lifting is wrapped up. Naylor, Donovan and Ferrer are quality headline additions, but the M’s have done plenty of work to round out the margins of the roster with improved depth to position them for the rigors of a long season. They’ll head into 2026 as a popular pick to win their division at the very least, and better health from their top starters could make Seattle one of the favorites in the broader American League overall.