ANALYSIS: Could Seattle Mariners Trade For a Young Infielder in the Offseason?
Most fans have already prepared for the 2025 offseason to be a disappointing one for the Seattle Mariners. Or, at least a typical one.
Despite free agents like Alex Bregman and Juan Soto being available, there's very little expectation that the Mariners are going to be big spenders in the free agent market. And that was before comments by Seattle owner/chairman John Stanton all but confirmed that after the season.
Even so, I still included Bregman in an opinion piece about three players the Mariners should target in the offseason.
When that story was published, one fan commented on "X" (formerly known as Twitter) about how he would prefer Seattle to trade for a younger infielder in a package including a prospect and a starting pitcher.
The fan, with the handle of @MarinersTrades, proposed packaging Luis Castillo and a prospect for a young third/first baseman like Mark Vientos, Jordan Westburg or Coby Mayo.
So that got me thinking, could the Mariners actually put together a package to secure a young star at one of its corner infield spots?
The simple answer is yes. But there's a couple problems that would need to be resolved for the deal to get done.
The first thing is Mayo. I'm not considering him a possible trade target. Merely because there's still questions about how good he actually is.
Mayo is ranked as the No. 8 prospect in all of baseball according to MLB Pipeline. But he's only played 17 games in the majors, which all were this season. He hit .098 (4-for-41) with no RBIs and no extra-base hits.
If Seattle does trade a starting pitcher, there's no way it's for an unproven player. So Mayo is a non-factor.
The second issue is Castillo's cost and no-trade clause. Castillo, on top of needing to sign off on a trade, is being paid $24.15 million a year through 2027 with a $25 million vesting option for 2028. He'll also be 32 years-old on Dec. 12.
In an article published by the Seattle Times' Adam Jude, one anonymous industry source said Castillo was the "least likely" of the five starting pitchers to be traded. Mainly because of all the reasons listed above.
Castillo proved he was still an upper-tier pitcher in 2024. His age isn't an issue. His salary definitely is.
Mama, Luis Castillo just killed a man. pic.twitter.com/A3JFxCtO8D
— Rob Friedman (@PitchingNinja) August 12, 2024
The Mariners would likely have to take on some of Castillo's contract or send cash over to make a deal more palatable for another team. Especially the New York Mets, Vientos' team. New York has the highest payroll in the league at $317,778,899.
But both teams' current status might make a deal get done easier.
Vientos plays for the Mets and Westburg plays for the Baltimore Orioles. Both teams can be considered contenders. If it's an issue about going to a team that can win a ring, Castillo likely won't have any problem waiving his no-trade clause for that one of those squads.
But it's not always about rings or money. There's a very good chance Castillo says "no" to getting moved strictly because he wants to stay in the Pacific Northwest. He's a respected presence in the locker room and has made himself an important part of the community.
But there's no way of knowing that for sure. And for the sake of this analysis, we're working on the assumption Castillo would agree to go to a contender.
Now on to the players Seattle would potentially get in the trade.
Vientos is just 24 years-old and isn't up for pre-arbitration until 2026. Same with Westburg, who's just nine months older than Vientos.
Both players would be long-term solutions for the Mariners at third base and are coming off excellent seasons for their respective teams.
Vientos batted .266 with 27 home runs and 71 RBIs in 2024. He hit a grand slam in Game 2 of a National League Championship Series on Monday and helped New York tie the best-of-seven NLCS 1-1.
MARK VIENTOS GRAND SLAM
— MLB (@MLB) October 14, 2024
THE @METS ARE RAKING IN LA 🤯 pic.twitter.com/DIQYRNusVa
Westburg hit .264 with 18 homers and 63 RBIs for the Orioles in 2024.
The issue for Baltimore and the Mets is what makes those players so appealing for the Mariners is exactly why there's not much incentive to trade them.
Vientos and Westburg are both young and cheap stars-in-the-making that are part of the futures for both teams.
New York, in particular, dealt with so many injuries this season that trading its most promising young player could take more than one top 100 player and Castillo.
That leads to another which players it would actually take to get Vientos and Westburg.
On face value, the most likely trade candidates for Seattle among its prospects are catcher Harry Ford and infielder Michael Arroyo.
Ford is projected for a 2025 call-up according to MLB Pipeline, but he's stuck in no-man's land right now. Mitch Garver is under contract with the Mariners through 2025 with a mutual option for 2026.
The Mariners are unlikely to move on from Garver's contract in the offseason. Even if they could, his value as the team's backup catcher and his synergy developed with George Kirby still gives the team value. Garver had a bad year at the plate in 2024, but he's still a solid defensive player at his worst and Seattle likely won't create another hole on the roster just to give Ford an avenue to make the big leagues.
Arroyo is one of many middle-infield prospects Seattle has along with Colt Emerson, Cole Young and Felnin Celesten.
Arroyo led minor league players 19 years-old or younger with 23 homers in 2024. He mainly played shortstop and second base with the team's Low-A club the Modesto Nuts and High-A affiliate Everett AquaSox this season. But he's played third base in spurts in the Mariners' farm system and has the arm for it.
Ford has also played left field, albeit sparingly, during his time in the minors.
A package of Castillo, Ford and Arroyo could move the needle enough for Baltimore and the Mets to consider trading Westburg or Vientos.
But neither team has a lot of motivation to do so. And with other pitchers on the trade market, they could potentially get better (and cheaper) deals while still fulfilling their need for starting pitching.
So, to answer the question, could Seattle fulfill a position of need with a young rising star? Yes. But it would take a lot. Maybe too much for the Mariners to part with.
But making a trade for a player like Vientos and Westburg would definitely show that Seattle is serious about winning while still adhering to their "don't spend" mentality.
Fans shouldn't hold their breath on Mariners making a blockbuster move. But it's one of several avenues that Seattle could pursue this offseason. If they want to.
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