Predicting 3 Mariners Offseason Moves, Including Major Trade

The Seattle Mariners fired the opening shots of this Major League Baseball offseason, but they've been relatively quiet since then.

Re-signing Josh Naylor to a five-year deal was the most important agenda item for the Mariners, but as of now, they've lost more talent than they've gained. Jorge Polanco signed with the New York Mets, Eugenio Suárez remains unsigned, and as of now, Seattle's opening day infield would include unproven youngsters at third base and second.

Uncertainty at this stage is acceptable, but soon, the Mariners will need to start wheeling and dealing again. Here's what Fastball On SI believes the club will do the rest of the way:

Trade for St. Louis Cardinals second baseman Brendan Donovan

Donovan and Arizona Diamondbacks superstar Ketel Marte have been the two main pieces the Mariners have been connected to on the trade market as of late. And in addition to Marte's decreasing likelihood of being dealt, Ken Rosenthal of The Athletic suggested Monday that Donovan's positional versatility might increase his appeal to Seattle.

While the Boston Red Sox have continued to be rumored as suitors for Donovan, the Mariners make the most sense by far, and their pitching prospects should appeal to a St. Louis team desperate to uncover young talent in the rotation to accelerate its rebuild.

Sign one more middle reliever

Sep 24, 2025; Cumberland, Georgia, USA; Washington Nationals relief pitcher Jose Ferrer (47) reacts after the Nationals defeated the Atlanta Braves at Truist Park. Mandatory Credit: Dale Zanine-Imagn Images | Dale Zanine-Imagn Images

Trading top catching prospect Harry Ford to the Washington Nationals for lefty José A. Ferrer was the surprise move of the winter for the Mariners so far, but it left the bullpen in a great place. Ferrer and Gabe Speier are the top lefties, while Seattle has multiple righty setup options as well in front of closer Andrés Muñoz.

Still, the relief market offers lots of depth options at this time of year, and sometime in the month of January, we think Seattle will take advantage of the market cooling off to land someone like Jose Leclerc or Tommy Kahnle for cheap.

Make a trade no one sees coming

Jerry Dipoto loves trades, and although he pulled off the deal to land Ferrer in November, he's still been awfully inactive by his own standards this winter. The Mariners shouldn't be expected to move any of their major league starters, but

Randy Arozarena and Luis Castillo are the two veterans who could theoretically be moved, as they're expensive and the former is entering his walk year. But the guess here is that the Mariners move one of their young position players at the top levels of the minors to bring in a veteran bat on a relatively cheap deal.

More MLB: Former 3-Year Mariners Hurler Announces Signing With Rival Angels