If the Seattle Mariners are going to make a big trade this offseason, there’s now one indication of who it could be with.

Here’s who Mariners could take at No. 3 overall in 2025 MLB Draft

MLB Network insider Jon Morosi reported Wednesday that per a source, the Boston Red Sox “are working to acquire one of the Mariners’ starting pitchers.” That comes on the heels of the Red Sox making a blockbuster deal with the White Sox for All-Star pitcher Garrett Crochet earlier Wednesday.

Seattle Times Mariners reporter Adam Jude had his own report shortly after, posting on social media that “Boston has been persistent in its pursuit of one Seattle’s starters.” He added that a hypothetical deal that would send Mariners pitcher Luis Castillo to the Red Sox for first baseman Triston Casas would “seem to make sense for both sides.”

Alex Speier, who covers the Red Sox for the Boston Globe, followed up on that, splashing some water on the fire at least when it comes to the names.

“Asked a source if there were legs to a deal involving Triston Casas for Luis Castillo,” Speier wrote on social media. “The answer was straightforward: ‘No.’”

So while specific names haven’t been pinned down yet, it at least seems clear that the Red Sox are interested in a trade for a Mariners pitcher. The level at which Seattle is interested, however, remains to be seen.

The M’s have been steadfast about wanting to keep their starting rotation intact, in particular their four youngest starters: All-Stars Logan Gilbert and George Kirby, and recent breakout pitchers Bryce Miller and Bryan Woo. Seattle president of baseball operations Jerry Dipoto said trading one of the Mariners’ young starters this offseason would be “Plan Z” when talking to the media at the end of the 2024 season, and he spoke this week at MLB’s winter meetings more about looking to trade from the team’s well-stocked farm system than from the big league club (click the link below for that story).

Dipoto shares how Mariners are being ‘very aggressive’ on trade market

It has been a quiet offseason thus far for the Mariners, who have made a minor addition in corner infielder Austin Shenton and expressed their interest in pursuing Japanese star pitcher Roki Sasaki, who was posted by his Nippon Pro Baseball team as available to MLB clubs this week.

The biggest news of Seattle’s offseason came Tuesday when the Mariners surprisingly ended up with the No. 3 overall pick in the 2025 MLB Draft despite entering the draft lottery with odds that put them most likely to get the 14th pick.

More on the Seattle Mariners

• Lucky Mariners just unexpectedly landed very high MLB Draft pick
• The Mariners will have a strong pitch for Japanese star Roki Sasaki
• Salk: The three Seattle Mariners to watch as surprise trade candidates
• Dipoto shares how Mariners are being ‘very aggressive’ on trade market
• Salk: No thanks on a Seattle Mariners trade for 3B Alec Bohm

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