White Sox acquire Luis Castillo, adding rotation depth amid limited pitching options

Chicago traded left-handed reliever Seranthony Domínguez, catching prospect Boston Smith and outfielder Nolan Jones to Seattle for right-hander Luis Castillo. The move gives the White Sox a veteran arm to add depth to a rotation that has struggled to find reliable starters this season. Castillo, who posted a 5.06 ERA with Seattle, will remain under contract for $22.75 million in 2026 and the same amount in 2027, though the trade reduces the 2027 obligation to roughly $10 million.

General manager Chris Getz said the acquisition addresses the immediate need for a starter after younger pitchers failed to develop as expected. The White Sox also benefited from the unexpected performance of Jordan Hicks, who regained form after being acquired earlier, and from the rapid rise of Boston Smith, who posted a .291/.450/.589 line across three minor-league levels before being dealt.

Analysts note that while Castillo offers a chance to improve the staff, his past performance and sizable contract pose a risk if he cannot elevate his play. The trade reflects Chicago’s limited market options and the urgency to reinforce the rotation before the season’s final stretch.