Seattle Mariners starting pitcher Luis Castillo (58) looks up during the first inning against Cleveland Guardians at T-Mobile Park on June 13. Steven Bisig-Imagn Images

New Details Emerge From Offseason Trade Talks Involving Seattle Mariners' Luis Castillo

Originally posted on Seattle Mariners on SI
By Brady Farkas | Last updated Jun 18, 2025 12:15 PM ET

Over the winter, there were trade rumors involving Seattle Mariners' All-Star Luis Castillo and the Boston Red Sox. While nothing happened, there was talk of the M's sending Castillo to Boston and receiving at least first baseman Triston Casas back.

Speaking on the "Marine Layer" podcast this week, noted Red Sox personality Jared Carrabis of the Section 10 podcast provided some more context about the discussions.

“(Luis Castillo) wanted his contract to be restructured. Taxes in Seattle are better than they are in Boston, so he wanted to be compensated for the difference”

Jared Carrabis backs up that the Mariners-Red Sox offseason trade talks were real, with some previously untold info

“(Luis Castillo) wanted his contract to be restructured. Taxes in Seattle are better than they are in Boston, so he wanted to be compensated for the difference”

Jared Carrabis backs up that the Mariners-Red Sox offseason trade talks were real, with some previously untold info pic.twitter.com/hJsFLePOhO
— Marine Layer Podcast (@MarineLayerPod) June 17, 2025

Castillo has a no-trade clause at this time, so it makes sense that he was in a position to negotiate, but that is not a detail that we had heard before.

Thus far, the Mariners have been rewarded for their decision to keep Castillo, as he's gone 4-4 with a 3.29 ERA through 14 starts. He's tossed six innings or more in four of his last five starts, giving up three earned runs or less in four of them as well.

As for Casas, he is out for the season after suffering a gruesome leg injury in early May.

Castillo will pitch against the Red Sox on Wednesday afternoon when the two teams finish out their season series at T-Mobile Park. First pitch is scheduled for 1:10 p.m. PT as Castillo pitches against All-Star Garrett Crochet.

He's 6-4 with a 2.24 ERA.

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

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