The Seattle Mariners find themselves at the center of trade talks going around MLB this offseason. They have clear needs, and the prospect capital to make a compelling offer to any team. Following Jorge Polanco‘s signing with the New York Mets, the names most closely linked to the Mariners have been second basemen Ketel Marte and Brendan Donovan. Now the question is how Seattle balances prospects and future flexibility to win in 2026.
With World Series aspirations, anything less at this point would be considered a failure by the front office. Jerry Dipoto and Justin Hollander have both said as much in the aftermath of Seattle’s ALCS exit. Even Cal Raleigh made sure of high aspirations from the team before inking his long-term contract. We saw this with how aggressive they were at the deadline and in signing Josh Naylor to a long-term deal so quickly. Because of geography and financial reality, Seattle has always treated the trade market as their primary path to impact talent. So now feels like the culmination of having built the deepest farm system in the league to now attack this offseason. With elite pieces on the table, the Mariners will have to decide which version of the future they’re willing to sacrifice.
Possible Trade Targets for the Mariners This Offseason
What Do They Have?
With one of the deepest farm systems in the league, they have built the prospect ammunition to make a move. But as with any big trade, the Mariners will have to give up real talent in order to get difference makers they believe can lead them to a World Series in 2026. Here we will see who could be available and what they offer any team in the future.
Borderline Untouchable
Colt Emerson (9) is the Mariners’ highest-rated prospect, listed 9th in the MLB Pipeline’s Top 100 prospect list. He is on the precipice of the 26-man roster and will be expected to contribute next season. With his versatility in the field at positions of need, there’s no world where he would be worth giving up.
Kade Anderson (23), drafted third overall in the 2025 Draft, was seen as a potential No. 1 pick, and was a steal at No. 3. Similar to Emerson, he is expected to play some role this season: to contribute on the mound in 2026. That makes it hard to see him involved in any trade.
Four Top 100 Prospects Potentially On the Table
While the cost of Emerson or Anderson would almost certainly be too rich, the Mariners’ depth of high-level talent in their system creates real trade flexibility. That flexibility comes at a price, and winning now would require surrendering future pieces the organization has spent years developing.
Lazaro Montes (29) has drawn comparisons to Yordan Alvarez. A polarizing prospect with raw elite power, but not a great hit tool as of now, and pretty limited in terms of his value. But the ceiling is as high as anyone in the minor leagues.
Ryan Sloan (44), another pitcher further away from the rotation timeline than Anderson at only 19. But in Mariner circles, he is seen as having the highest ceiling of any pitcher in their system, and is probably the least likely of these four to be a part of any deal.
Michael Arroyo (63), an infielder who projects at second base. Arroyo is a compact, powerful yet disciplined hitter who has climbed the ladder quickly and is developing into a serviceable player.
Jurrangelo Cijntje (90), a switch pitcher, Cijntje is a unique prospect. He is better from the right side, but the Mariners have allowed him to pitch from both sides to see how it develops. A fascinating talent, nonetheless, that a pitching staff could be intrigued to work with.
Ketel Marte
The Player
Marte represents the high-certainty, high-cost path. Arguably the best second baseman in the majors, he fills a clear need. While 32 years old, he has five years of control on a reasonable contract. As a switch-hitter, he adds much-needed versatility to a lineup that leans heavily left-handed. He is still producing at an elite level for the Arizona Diamondbacks, sitting in the upper echelons of the league in terms of batting average and expected slugging. He provides a rare combination of offensive explosiveness, high-end contact quality, and strong plate discipline. For a Mariners team that struggled to convert opportunities with runners on base, Marte fits the lineup perfectly. It appears he is aging well, with still elite bat-speed and velocity numbers.
He’s a needle-mover that would mean they might not need another addition to the lineup. Reports continue to swirl over a trade, and Seattle seems to hold a very real interest. But the real question is, how much would it cost?
The Cost
Marte is a difference maker, and Arizona will rightly require a hefty sum. The cost for this level of talent can be extortionate, as we saw with the Juan Soto trade. Marte won’t command that sort of haul, but any deal for Marte would come at a premium. While Arizona would benefit from moving on from his contract to disperse funds to other parts of the roster, they still hold all the cards. Luckily for the Mariners, they have what the Diamondbacks will require, and that’s pitching. Seattle would have to decide whether to protect its rotation depth or surrender elite talent. Arizona will certainly ask for Bryce Miller. But it is hard to see Seattle entertaining any offers with one of their starting rotation members involved. Based on recent trade markets and Arizona’s roster construction, a Marte deal would likely require the Mariners to surrender multiple high-ceiling prospects.
Mariners? Mets? Rays? ?@Ken_Rosenthal explores who fits the D’backs need for starting pitching if they were to trade Ketel Marte… pic.twitter.com/3SPUo7y7Gc
— Foul Territory (@FoulTerritoryTV) December 18, 2025
Arizona’s Opening Package
Bryce Miller + Cole Young/Logan Evans + Ryan Sloan + Michael Arroyo
Realistic Package
Sloan + Montes + Jonny Farmelo + Teddy McGraw
A return that would give Arizona three Top 100 prospects and an additional arm aligned with their roster needs. Logan Evans or Emerson Hancock could also be involved.
Brendan Donovan
The Player
Donovan represents the more realistic, lower-cost alternative. He drives his offensive production with a contact-first approach and a high level of consistency. His expected batting metrics remain strong despite below-average power indicators, driven by elite bat control and swing decisions that keep his strikeout rate among the lowest in baseball. With the St. Louis Cardinals, Donovan consistently squares up the baseball and rarely swings and misses. As a hitter, he is exactly the kind of bat the Mariners are looking for. In the mold of Naylor, he can give good at-bats, be reliable to get on base, and help drive in runs.
He offers the versatility to play anywhere in the infield and even the outfield if the Mariners want to give rest days to their outfielders. Donovan offers a high-floor offensive profile built on elite bat control and contact skills. He would provide Seattle with certainty in the middle of the order, but the team would still realistically need to make additions elsewhere.
The Cost
Despite some fans’ expectations in St. Louis, Seattle is unlikely to give up more than one Top 100 prospect and a fringe roster player such as Ben Williamson or one of Evans or Hancock. Donovan has just two years of club control remaining, and while he would clearly improve Seattle’s lineup, his ceiling is nowhere near Marte’s. That combination naturally caps his market value, even if it still requires Seattle to part with a Top 100 prospect. For St. Louis, the appeal would come from converting a shorter-term asset into controllable depth paired with an elite young talent.
St Louis’ Opening Package
Montes + Williamson + McGraw
Realistic Package
Cijntje + McGraw + Tai Peete
Here, St. Louis would get a top-100 prospect and two of the Mariners’ top 15 prospects.
Main Photo Credit: Denis Poroy-Imagn Images
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