The essentials
White Sox acquired pitcher Luis Castillo from the Mariners to bolster their rotation.
The Chicago White Sox acquired pitcher Luis Castillo from the Seattle Mariners ahead of the trade deadline. Castillo posted a 5.06 ERA with Seattle during the 2026 season.
The move comes as the White Sox hold the AL Central lead heading into the deadline. The Mariners, trailing the Houston Astros in their division, held a 54-58 record at the time of the trade.
Other ways to read this story.
Alternative framings generated by SigNews. These are not independent sources or attributed quotations.
White Sox Strengthen Rotation While Leading AL Central
The acquisition reinforces Chicago's position atop the division, adding rotation depth as they push toward postseason contention. Adding Castillo's experience addresses pitching needs during their stretch run.
Mariners Part with Castillo as Playoff Hopes Fade
Seattle's trade of Castillo reflects their distance from division leader Houston and commitment to reshaping the roster. The move signals a shift toward future planning rather than competing in 2026.