The Boston Red Sox and Chicago Cubs have both managed to swing blockbuster trades this winter. Boston acquired left-handed ace Garrett Crochet while Chicago recently brought in superstar Kyle Tucker. But both of these teams are likely searching for more.

One main target for both these clubs is Seattle Mariners pitcher Luis Castillo, who’s in the middle of a $108 million contract that sees him paid through 2028. Still, interest in Castillo is high. “As prices for high-end starting pitchers have swelled this week, the Mariners have received an increasing number of calls from other teams interested in veteran starter Luis Castillo,” Ryan Divish and Adam Jude of the Seattle Times wrote.

Both the Red Sox and Cubs have reportedly checked in on the Mariners right-hander. Boston has already added an ace, but it’s looking for more and there’s planet more for the team to offer.

“The Boston Red Sox have been persistent in their pursuit of a Mariners starter, a source said, even after the Red Sox traded four prospects to the Chicago White Sox for Garrett Crochet on Wednesday,” Divish and Jude wrote. “Earlier this offseason, the Mariners shot down a one-for-one offer that would have sent one of Seattle’s young starters, Bryce Miller or Bryan Woo, to Boston for 24-year-old first baseman Triston Casas.”

Casas could still be the centerpiece of a deal, but it likely wouldn’t be a one-for-one for Castillo. The Cubs remain in pursuit as well. Chicago has second baseman Nico Hoerner they could move and the Mariners would likely love that option a lot.

“The Mariners and Cubs have had discussions this offseason about alignment on various deals, and the Cubs have expressed interest in Castillo, a source said,” Divish and Jude wrote. Hoerner would likely be moved in this potential trade. The Mariners reportedly have quite a bit of interest in him. Seattle needs an infielder and Hoerner would fill that hole.