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2025-26 MLB Offseason Recap: Seattle Mariners

Originally posted on New Baseball Media
By Chris Studley | Last updated Feb 25, 2026 3:32 PM ET

The 2025 Seattle Mariners came one win away from the team’s first-ever American League pennant. While Seattle was unsuccessful in its quest for a World Series berth, the team is still very much a contender to make it to the Fall Classic in 2026. And to get there, the M’s made some moves to bolster both the bullpen and the top-half of the lineup.

Additions

For several years, the Seattle Mariners’ lineup was filled with swing-and-miss heavy power-hitters — and that hasn’t changed from 2025 to 2026. However, Seattle made contact somewhat of a priority over the past few months.

Brendan Donovan, one of the best pure contact hitters in the game, was brought over via trade from the Cardinals. The trade cost Seattle prospects Tai Peete and Jurrangelo Cijntje, two high-ceiling players. However, it does add a lot to the current Mariners team, which is important given the win-now position the organization is in.

Simply put, Donovan is one of those tough-to-get-out hitters. For many hitters, there’s always that one kind of pitch — usually a breaking ball or a splitter/change — that gives trouble. However, with Donovan, he didn’t have a pitch that he whiffed on more than 29% of the time over the last three seasons.

(via New Baseball Media)

That, coupled with some power and an overall ability to work pitchers, makes Donovan a good leadoff hitter option for Seattle. And, he helps solidify the infield situation for the Mariners.

The other big piece added this winter was Jose A. Ferrer, the dynamic, hard-throwing reliever from the Nationals. Ferrer was acquired in a December 2025 trade with Washington.

Ferrer was a terrific late-inning reliever for the Nationals over the past several years. He does have some closing experience, although that won’t be his role in Seattle with Andres Munoz around. Still, the addition of Ferrer gives the Mariners another lefty match-up, important given how much the team used Gabe Speier against left-handed hitters.

Aside from those two, the M’s also added some much-needed depth. Rob Refsnyder is a terrific platoon option, while lefties Josh Simpson and Robinson Ortiz are lefties with options.

Losses

Seattle was able to retain Josh Naylor, the first baseman acquired by the M’s just before the 2025 Trade Deadline. Naylor received a five-year deal to stick with the Mariners, a move that solidifies the first baseman situation for years to come.

However, there were still some significant losses.

The Mariners saw Jorge Polanco (Mets) go to free agency. Polanco had a great bounce-back campaign with Seattle in 2025 and then played a key role for the team in the playoffs.

Eugenio Suarez, re-acquired by the Mariners in July, went to the market and stuck around in the free agent pool for some time. He eventually signed with the Reds, going back to the team where he starred for years before he arrived for his first stint in the Pacific Northwest.

Harry Ford, one of Seattle’s top prospects, was flipped to Washington in the Ferrer trade.

Overview

The Mariners still have their rotation intact. Plus, the superstars in the lineup will be around for the foreseeable future, meaning the window to win a title is open.

This winter was all about adding complements to the core — and indeed, that was done.

This article first appeared on New Baseball Media and was syndicated with permission.

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