Mariners shake up roster, trading Luis Castillo to the White Sox ahead of deadline

By: The Associated Press Posted: 10:02 PM CDT Saturday, Aug. 1, 2026

SEATTLE (AP) — The Seattle Mariners have traded right-hander Luis Castillo to the Chicago White Sox in exchange for right-hander Seranthony Domínguez, outfielder Nolan Jones and catching prospect Boston Smith and cash considerations, the Mariners announced Saturday night.

Read this article for free:

or

Already have an account? Log in here »

To continue reading, please subscribe:

*First annual payment billed as $205.00 + GST for one year. This annual subscription will automatically renew at $233.00 + GST every 52 weeks (10% off the regular annual price of $259.35). Offer available to new and qualified returning subscribers only. Cancel any time.

Read unlimited articles for free today:

or

Already have an account? Log in here »

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.

The White Sox, meanwhile, lead the AL Central by 2 1/2 games with a 58-52 record.

Seattle Mariners starting pitcher Luis Castillo (58) throws a pitch against the Los Angeles Dodgers during the first inning of a baseball game Tuesday, July 28 2026, in Los Angeles. (AP Photo/Wally Skalij)

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. ___ AP MLB: https://apnews.com/hub/mlb