The Seattle Mariners are heating up their offseason activities as they pursue Roki Sasaki while navigating trade talks involving veteran pitcher Luis Castillo. Reports indicate that the Mariners and Boston Red Sox have discussed a potential trade that would send Castillo to Boston in exchange for first baseman Triston Casas, although those talks have not progressed.

Castillo, who is 32 and has a no-trade clause, is the highest-paid pitcher on the Mariners' roster and had a solid season with a 3.64 ERA and 175 strikeouts. Seattle's President of Baseball Operations, Jerry Dipoto, has emphasized that trading a pitcher is a last resort, but Castillo's age and salary make him a likely candidate if a trade does occur.