The Seattle Mariners had a brutal 2024 season. From a ten-game lead in the American League West to missing the playoffs, disappointing does not begin to cover it. They finally broke their playoff drought in 2022 but could not capitalize in 2024. Heading into the offseason, the Mariners must make a trade to improve their offense and may need to sacrifice a pitcher to do so.

The Mariners posted the second-worst team batting average in Major League Baseball last season. Only the White Sox, the worst team in AL/NL history, was worse. While they put up a solid record despite that record, they need to pick up their offense to make a playoff run. They were a good team because of their top-notch starting rotation and should shed a piece of it to get a hitter.

The question is which pitcher should they part with? Well, that depends on who they are getting back. The most valuable pitcher on the Mariners is Bryan Woo. The 24-year-old had the best ERA on the team with a 2.89. If they are going to go after the upper-echelon trade pieces, Woo will be at the center of the package. Logan Gilbert, George Kirby, and Bryce Miller are the other pitchers who could be moved.

When the Mariners take the field for the 2025 season, they need to have another strong middle-of-the-order bat on their team. That could be Pete Alonso, who may have played his last game for the Mets. Seattle is the perfect fit for the slugging first baseman and they have the money to spend. If they don't land the Polar Bear, they should attack their problem through a trade.

Who could the Mariners land this offseason? 

Chicago White Sox outfielder Luis Robert Jr. (88) reacts after striking out against the Los Angeles Angels during the third inning at Guaranteed Rate Field.
Kamil Krzaczynski-Imagn Images

Luis Robert Jr of the Chicago White Sox is the biggest fish in the trade pool this winter. The centerfielder was a part of the worst team in baseball history and the franchise is looking to tear it down even more. Robert nearly won Rookie of the Year in 2020 and finished 12th in 2023 MVP voting. Injuries have derailed the first half-decade of his career but he has proven he can be a great player.

Woo would have to be the main piece going back to the White Sox. While they are looking for pieces for the future, Woo could be considered that at 24 years old. The Mariners should be willing to part with him because of their stellar rotation and lackluster offense. The only issue here is that Julio Rodriguez already plays center, so someone will have to move to a corner outfield position.

Back at the trade deadline, ESPN's Jeff Passan reported that the Orioles were looking to move Ryan Mountcastle. The first baseman remained in Baltimore but the team fizzled out down the stretch. While there is a bright future for the franchise, it might not include Mountcastle. He would be a great fit for the Mariners, who need infielders and power hitters.

This trade would not require Woo but could involve one of the other starting pitchers. Logan Gilbert is the oldest of the group and closest to free agency, so he would be easier to trade. Arbitration years are coming up and free agency down the line that the new Orioles' ownership could pay for. If Corbin Burnes returns, he will be a great second option. This is a trade that benefits both sides and would set the Mariners up well.

Where else could the Mariners improve? 

Free agency will be interesting for the Mariners this season. They have space under the tax threshold and holes in their infield. Gleyber Torres, Alex Bregman, and Willy Adames will all be high-priced free agents at the positions they need. Pete Alonso would be a perfect fit at first base for Seattle. Whether Seattle, a team not known for spending big money, gets involved in those sweepstakes is unknown. What they don't get through free agency they should attack through trade.

Starting pitching is important and developing this many top-line starters under 30 is very impressive. The Mariners should take advantage of that by dealing one of them for a player they need. Luis Robert and Ryan Mountcastle are just some of the players they could target. Cody Bellinger, Brent Rooker, and Lane Thomas all could be traded this offseason.