Red Sox Predicted To Target $108M Superstar In Blockbuster Trade With Mariners

Could Seattle provide the Red Sox with their next staff ace?

Jul 30, 2024; Boston, Massachusetts, USA; Seattle Mariners pitcher Luis Castillo (58) has a meeting on the mound with catcher Cal Raleigh (29) during the fifth inning against the Boston Red Sox at Fenway Park. Mandatory Credit: Eric Canha-Imagn Images / Eric Canha-Imagn Images

There are several paths for the Boston Red Sox to pursue starting pitching this winter, but they still have to pick one.

In 2024, the lack of a true ace atop the rotation ultimately sank the Red Sox at the tail end of the summer. Tanner Houck, Brayan Bello, and Kutter Crawford are all solid building blocks, but they need a number-one to set the tone in front of them for the 2025 campaign.

The Red Sox could look to free agency to find that ace, but starting pitching prices appear to be exorbitant this winter. While a trade can be more difficult to find, it may be the most cost-effective way for Boston to get what it needs.

Much like in free agency, there are a few top candidates among ace-quality starting pitchers to be traded this winter. However, one name has begun to emerge as a top contender: Luis Castillo of the Seattle Mariners.

On Thursday, Miles Houston of FanSided predicted that the Red Sox would seek a trade for Castillo, who has three years left on his five-year, $108 million contract, with the offensively challenged Mariners.

"Castillo, 31, pitched to a 3.64 ERA, a 3.91 FIP, and an ERA+ of 101 in 175.1 innings of work. While 2024 was a down year for Castillo's standards, he's primed for a bounceback 2025 and would be an excellent ace for Boston's rotation," Houston said.

"In his eight seasons, in addition to being an ace, Castillo has demonstrated his elite durability. In 2023, he led all of MLB, with 33 games started, just three shy of his total in 2024, and with the Red Sox's previous struggles with durable starting pitching, he would be a welcome fit in Boston."

There is a growing sense that Castillo could be the Mariners pitcher that becomes available, because their other four starters are still arbitration-eligible or pre-arb. And that could work out well for the Red Sox, because the righty's more expensive contract could prompt Seattle to demand a lesser prospect package.

The deal is by no means a guarantee, but if there's any way for the Red Sox to add Castillo without giving up a top-four prospect, Jarren Duran, or Triston Casas, they should jump at the opportunity.

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