Red Sox Predicted To Bring $108M Mariners All-Star To Boston In Blockbuster Trade

One more big rotation piece for this Red Sox club?

Jul 11, 2023; Seattle, Washington, USA; American League pitcher Luis Castillo of the Seattle Mariners (58) and musician The Kid Mero talk before the game at T-Mobile Park. Mandatory Credit: Steven Bisig-Imagn Images | Steven Bisig-Imagn Images

It sure doesn't seem like the Boston Red Sox believe their starting rotation is a finished product.

Trading for Garrett Crochet makes the projected rotation a lot scarier on paper, but there are still some question marks. Is Lucas Giolito ready to make 30 starts again? Should Kutter Crawford be a full-time starter moving forward? It's all fairly murky.

To that end, the Red Sox have stayed active on the trade and free-agent fronts in their continued search for another strong starter. They've discussed trades with the Seattle Mariners, who have one of the strongest rotations in baseball, but will those talks ever result in a move being made?

Brian Murphy of MLB.com predicted that the Red Sox would come to an agreement with the Mariners involving three-time All-Star Luis Castillo, possibly involving either starting first baseman Triston Casas or top shortstop prospect Marcelo Mayer.

"Despite unloading four prospects for the southpaw, the Red Sox still possess a lot of burgeoning bats whom they could dangle in a deal. Many of those players are infielders, which is what the Mariners are looking for," Murphy said. "Could a Castillo trade involve slugging first baseman Triston Casas or No. 2 prospect Marcelo Mayer?"

"Boston has the pieces to get Castillo, who is under contract for at least three more seasons (he has a vesting option for 2028) and is annually dependable for a sub-4.00 ERA, at least 170 innings, plenty of strikeouts and not too many walks."

Castillo, 31, signed a five-year, $108 million extension with the Mariners before the 2023 season, during which he made the third and final All-Star appearance of his career thus far. He wasn't bad in 2024, though, posting a 3.64 ERA in 175 1/3 innings.

Giving up either Casas or Mayer for Castillo is a huge risk, though, one that would surpass the discomfort the front office must have felt at any point during the Crochet trade. Both are potential impact bats (Casas has already been one at times), and letting impact bats walk is the stuff that gives executives nightmares for years to come.

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