The Seattle Mariners are back in the market for a veteran infield bat after it became clear that Jorge Polanco won’t be returning. That leaves the front office with a familiar offseason challenge - finding a proven hitter who can bring both production and leadership to a young, evolving roster.
Two names have surfaced as potential fits: Brendan Donovan of the St. Louis Cardinals and Ketel Marte of the Arizona Diamondbacks.
Both are All-Stars, both bring something different to the table, and both would fill a clear need in Seattle’s lineup. The question now is: Which direction do the Mariners go?
Brendan Donovan: Versatility, Value, and Control
Let’s start with Brendan Donovan, who checks a lot of boxes for a team like Seattle. He’s younger, more affordable, and can play just about anywhere on the field.
According to reports, the Mariners are one of two frontrunners in trade talks with the Cardinals, and discussions have included top-100 prospects Lazaro Montes (No. 29 overall) and Jurrangelo Cijntje (No. 90).
Donovan doesn’t bring the same power potential as Marte, but that’s not necessarily a dealbreaker. What he does bring is a high-contact bat, athleticism, and the kind of defensive flexibility that’s become increasingly valuable in today’s game.
He’s primarily a second baseman but has logged innings at shortstop, third base, first, and both corner outfield spots. That kind of versatility is gold for a Mariners team trying to fit in young talents like Ben Williamson, Cole Young, and Colt Emerson.
Offensively, Donovan had a strong 2025 campaign, hitting a career-best .287 with 10 home runs, 32 doubles, a .353 OBP, and a .775 OPS over 118 games. He’s a left-handed hitter and a former Gold Glove winner at the utility spot - a rare combo that makes him an ideal plug-and-play option for a team that values defense and on-base skills.
He’s also under team control for two more seasons and projected to make a modest $5.4 million in arbitration next year. For a front office that’s always mindful of payroll and long-term flexibility, that’s a key selling point.
Ketel Marte: Star Power and Stability
If Donovan represents value and versatility, Ketel Marte brings star power and a proven track record of elite production. The 32-year-old switch-hitter was an All-Star again in 2025 - his third selection - and put up numbers that speak for themselves: a .283 average, .376 OBP, .517 slugging, and an .893 OPS with 28 home runs and 28 doubles in 126 games.
Marte has been locked in at second base since 2022, but his defensive history is broad. He came up as a shortstop, has played nearly 175 games in center field, and has even seen time at third base.
That versatility is still there, even if he’s more settled now. For Seattle, he could slot in at second or third and immediately become one of the most dangerous bats in the lineup.
Contract-wise, Marte is signed through 2027 with a club option for 2028 as part of a six-year, $116.5 million deal. That’s a significant commitment, but it’s also seen as team-friendly for a player of his caliber. He’s not just a veteran presence - he’s a middle-of-the-order threat who could anchor Seattle’s offense for years.
There is, however, a bit of urgency tied to Marte’s situation. Early next season, he’ll qualify for 10-and-5 rights - 10 years in the majors, five with the same team - which would give him full no-trade protection.
That puts pressure on Arizona to act now if they’re serious about moving him. Once those rights kick in, their leverage drops significantly.
Trade Landscape: Timing and Leverage
The dynamics around each player are different. In Marte’s case, Arizona may not have to trade him - but the clock is ticking.
Once he gains veto power, any deal becomes that much harder to pull off. There’s also the human side of this.
Marte’s name has floated in trade rumors before, and while he’s under contract, there’s always the question of how much longer he wants to stick around if the team keeps dangling him in talks.
With Donovan and the Cardinals, the urgency isn’t quite the same. St.
Louis doesn’t need to move him, but there’s a new president of baseball operations in Chaim Bloom, and it looks like he’s ready to shake things up. If the Cardinals are aiming to retool or pivot, moving a valuable, controllable player like Donovan could bring back a strong return - especially from a team like Seattle that has the prospect capital to make it happen.
The Fit for Seattle
Both Donovan and Marte would be significant additions for the Mariners - just in different ways.
Donovan gives Seattle a high-floor, low-cost option who can play multiple positions and fit seamlessly into a lineup that’s still taking shape. He won’t hit 30 homers, but he gets on base, plays solid defense, and gives Scott Servais flexibility with his daily lineup card.
Marte, on the other hand, would be a statement move. He’s a legitimate star, a switch-hitter with power, patience, and postseason experience. He’d give the Mariners a true difference-maker in the infield and a veteran bat capable of carrying stretches of the season.
The decision may come down to what Seattle is willing to give up. Marte will cost more - both in terms of prospects and payroll. Donovan, while still expensive in trade value, offers more financial flexibility and years of control.
Either way, the Mariners have options. And if they’re serious about contending in 2026, adding one of these two could be the kind of move that helps push them over the top.