Oct 16, 2025; Seattle, Washington, USA; Seattle Mariners pitcher Luis Castillo (58) walks off the mound after being relieved against the Toronto Blue Jays in the third inning during game four of the ALCS round for the 2025 MLB playoffs at T-Mobile Park. Mandatory Credit: Stephen Brashear-Imagn Images Stephen Brashear-Imagn Images

Mariners Urged To Cut Ties With $108 Million Star In Blockbuster Trade

Originally posted on Fastball on SI | By Zach Pressnell | Last updated Oct 31, 2025 3:00 PM ET

The Seattle Mariners were one of the best teams in the league this year. But they fell short of the ultimate prize as they lost to the Toronto Blue Jays in the American League Championship Series.

As the offseason begins, the Mariners are going to need to make some big moves in the offseason. They're set to lose stars like Jorge Polanco, Josh Naylor, and Eugenio Suárez in free agency. Seattle is going to need to be active in free agency, but there's also a chance it looks to make some big trades. The Mariners could look to trade away a player or two, but they could also look to add to the roster.

Adam Jude of the Seattle Times recently suggested the Mariners could look to trade Luis Castillo in the offseason, but a deal won't be as simple as some may assume.

Mariners could look to trade Luis Castillo this winter

"Rumors swirled about Castillo on the trade block last offseason, and that could be the case again this winter," Jude wrote. "This wouldn’t be an easy move to orchestrate on multiple fronts. Castillo, first off, is an enormously popular figure in the Mariners clubhouse. He’s also been enormously productive and durable, posting a 3.46 ERA across 106 starts over the past three and a half seasons in Seattle.

"He’s also the Mariners’ highest-paid player, scheduled to earn $24 million in each of the next two seasons, with a $25 million vesting option for 2028. The Mariners have given no indication they would want to trade Castillo or that they need to offload his contract, and it would be challenging to get equal value in return for him."

Castillo's contract handicaps the Mariners in free agency a bit.

The Mariners need to add some talent to replace their free agents if they can't re-sign them. They're not going to be able to comfortably find the money to sign the stars they need if Castillo's contract is still on the books.

The Mariners could take minimal prospect return in a deal for Castillo if it means the other team is taking on his entire contract. Either way, a trade like this would make plenty of sense for Seattle this offseason.

More MLB: Blockbuster Mock Trade Sends Tarik Skubal To Mariners In 3-For-1 Deal

This article first appeared on Fastball on SI and was syndicated with permission.

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