Rumblings of the Boston Red Sox completing a trade for Seattle Mariners pitcher Luis Castillo are intensifying. And a top MLB insider recently proposed a trade scenario that would make a deal a “win-win” for both teams.

Heading into the offseason, the Red Sox front office had an edict from the very top to improve the roster by any means necessary. It is an understandable reaction to a trio of .500 or worse seasons for the team. That is why they made a strong push for top free agent Juan Soto.

Related: Boston Red Sox rumors reveal 2 SP targets following Garrett Crochet trade

However, despite their best efforts, Boston finished well behind the New York Mets in the Soto sweepstakes. While they struck out trying to sign the best player in free agency, they quickly bounced back by completing a blockbuster trade for the best player available on the trade market. All-Star pitcher Garrett Crochet.

The Red Sox have been linked to several other players recently. But the most notable MLB rumor is of them attempting a second trade for a big-time pitcher. This time for Seattle Mariners veteran Luis Castillo. MLB.com insider Mark Feinsand added to the speculation on Monday when he wrote “The Red Sox would seem like a strong match with the Mariners.”

However, what could the return before Seattle in a trade for one of the better pitchers? That was also revealed Tuesday.

• Luis Castillo stats (2024): 11-12 record, 3.64 ERA, 1.169 WHIP, 175 strikeouts, 175.1 innings pitched

Boston Red Sox would have to fork over a pair of top infield prospects in a Luis Castillo trade?

“[The Mariners] should keep all of their young starters and be willing to move Castillo, which would also lessen their future financial exposure and potentially help them acquire more bats,” The Athletic’s Jim Bowden wrote on Tuesday. If the Red Sox don’t land free-agent ace Corbin Burnes, which they are trying to do, they could pivot and sign Bregman to play third base, which would necessitate a move of Rafael Devers to first.

“And allow them to trade [Tristan] Casas and a corner infielder such as prospect Blaze Jordan for Castillo to further improve their rotation,” the former MLB GM wrote. “Casas, 24, profiles as a future 25-30 home run power bat. He won’t be eligible for arbitration until 2026. Jordan, who will turn 22 this week, was a third-round pick in 2020. He batted .261/.305/.388 with seven homers and 22 doubles last season at Double-A. A win-win for both organizations.”

Luis Castillo contract: Five years, $108 million

While both teams would like to hold on to players like Castillo and Casas for different reasons, adding the other would help address big needs for both franchises this offseason. Pitching for the Boston Red Sox and hitting for the Seattle Mariners.

Related: Ichiro working to help recruit top free agent to Seattle Mariners