Red Sox Predicted To Acquire $72.5 Million Mariners All-Star In Blockbuster Trade

Can the Red Sox pull off this stunning trade?

Seattle Mariners logos help set the scene in the Seattle Terrace dining and shopping area of the Flight of Dreams complex in Japan. 636747024810893983-20-Seattle-Mariners-logos-help-set-the-scene-in-Seattle-Terrace-dining-and-shoppoig-area-of-the-Flight-of-Dreams-complex-in-Japan.-Photo-Harriet-Baskas.JPG / Harriet Baskas for USA TODAY

What do the Boston Red Sox plan to do to finish the starting rotation this winter?

Even in the wake of the Garrett Crochet deal, it seems that the Red Sox consider themselves still to be one arm away from their ideal rotation. It makes sense--in today's game, relying on five starters to pitch full, healthy seasons just isn't realistic anymore.

Word of Chief Baseball Officer Craig Breslow's aggression on the trade market is still echoing throughout Major League Baseball. That may be encouraging news, sure, but who is Breslow's next target? And more importantly, are they attainable?

Luis Castillo of the Seattle Mariners is looking like a more viable option by the day. He's a three-time All-Star but the most expensive pitcher on his own team, and though his 3.64 ERA a season ago might lead some to believe his best days are behind him, he's still racking up valuable innings.

On Friday, Zachary D. Rymer of Bleacher Report predicted that the Red Sox would pull off a blockbuster trade for Castillo, who is under contract for the next three seasons with a vesting option for a fourth.

"Castillo's fastball has been one of the most valuable pitches in baseball over the last two seasons. He's also an iron man, as he's made at least 30 starts five times in his eight seasons in the majors," said.

"Even with $72.5 million remaining on his deal, Castillo could have enough value on his own to fetch a quality bat for Seattle's offense. Maybe even a great one, provided the club is willing to eat some of his contract."

When it comes to Seattle as a trade partner, the return likely has to start with a big-league-ready bat. Triston Casas and Wilyer Abreu have been thrown around often and even Jarren Duran's name has surfaced, though it makes little sense for the Red Sox to trade their team MVP from last season.

At some point this offseason, there could well become a time when Seattle is desperate enough for offense that trading for Abreu is their best option, while also getting out from under a hefty portion of the Castillo contract. That may play right into the Red Sox's hands.

More MLB: Red Sox Predicted To Acquire $50+ Million All-Star In Free Agency Blockbuster