Mariners could set up Mets for next blockbuster trade after monster Juan Soto deal

Now that the New York Mets have landed the biggest fish in free agency after inking Juan Soto to a $765 million contract, they can turn their attention toward upgrading their starting rotation during the offseason. And that's where the Seattle Mariners might be able to help.

Soto's contract could limit the rest of the Mets' activity on the free agent market this offseason (theoretically, of course; knowing Steve Cohen, he may never stop spending). That may force the Mets to go the trade route if they plan on adding any more significant pieces during the offseason.

After president of baseball operations Jerry Dipoto had previously squelched any possibility of the club dealing from its pitching depth, he appears to have changed his tune. According to Alex Speier of the Boston Globe, the Mariners have “expressed willingness” to listen to offers on veteran right-hander Luis Castillo, and perhaps the Mets would make an intriguing trade partner.

Mariners willing to listen to offers on Luis Castillo with focus on improving offense

It's easy to understand why the Mariners wouldn't want to part with one of the most talented arms in their rotation; Castillo finished the 2024 season with a 3.65 ERA in 175 1/3 innings over 30 starts. But if Seattle is serious about fixing its lack of offense, trading away a pitcher of Castillo's caliber to acquire some bats might be the only way to go about it.

Castillo is owed roughly $72 million over the next three years, which is a reasonable rate for a pitcher of his caliber – especially compared to the exorbitant cost of arms on the free agent market. He also has a $25 million vesting option for 2028. That price tag could seriously interest the Mets, but the Mariners will be looking for a hefty return to help improve their offense.

Yes, offloading Castillo's contract could give the club some more financial flexibility to go out and pick up a free agent bat like former Mets slugger Pete Alonso, but the Mets would have to offer some significant assets (likely in the form of high-level prospects) in return.

It doesn't sound like a Castillo trade is imminent by any means, but it's a storyline to monitor during this week's Winter Meetings in Dallas. If moving the veteran right-hander can help the Mariners improve their offense, it might be worth it.

More Mariners content from SoDo Mojo