The Chicago White Sox are buying in their World Series contention window ahead of Monday’s MLB trade deadline.
The White Sox, with an AL Central-leading record of 58-52, are acquiring starting right-handed pitcher Luis Castillo in a trade with the Seattle Mariners for reliever Seranthony Dominguez, outfielder Nolan Jones and catching prospect Boston Smith, according to a report from ESPN on Saturday.
Castillo has posted a 5.06 ERA in 99 ⅔ innings this season.
The struggling Mariners, who are four games below .500 and trail the Houston Astros by three games in the AL West, elected to part ways with one of their longest-tenured players ahead of Monday’s trade deadline.
Castillo, 33, is under contract through the 2027 season with a vesting option for 2028. He is 3-9 with 86 strikeouts and a 5.06 ERA across 99 2/3 innings.
The Mariners have a surplus of starting pitching options. At one point in the 2026 season, manager Dan Wilson paired Castillo and right-hander Bryce Miller in a “piggyback” to ensure Seattle’s six starting pitchers were all able to regularly appear in games.
Without Castillo, the Mariners still have Miller, former first-round pick Emerson Hancock, George Kirby and former All-Stars Logan Gilbert and Bryan Woo.
Domínguez, 31, is 4-3 with a 4.10 ERA in 42 games this season. Jones, 28, did not appear in a game for Chicago, instead splitting his time between Triple-A Charlotte and Triple-A Columbus, the top affiliate for the Cleveland Guardians.
Smith, 23, is hitting .291 with 22 home runs and 58 RBIs across stints at three minor league levels.
The Washington Nationals selected Smith in the sixth round of the 2025 MLB draft, and traded him to Chicago in March for utility man Curtis Mead.
