Sources: White Sox acquiring Castillo from Mariners in tradeJesse RogersAug 1, 2026, 10:43 PM ETClose
- Jesse joined ESPN Chicago in September 2009 and covers MLB for ESPN.com.
The Chicago White Sox are acquiring right-handed pitcher Luis Castillo from the Seattle Mariners for reliever Seranthony Dominguez, outfielder Nolan Jones and catching prospect Boston Smith, sources told EPSN’s Jeff Passan.
Castillo, 33, is 3-9 with a 5.06 ERA in 17 starts this season, giving up 107 hits in 99 1/2 innings pitched. He has a career 3.65 ERA over 10 seasons, though he’s having the worst year of his career.
Castillo is in the fourth year of a five-year, $108 million contract which has a vesting option for 2028.
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Dominguez, 31, was 4-3 with a 4.10 ERA and 12 saves over 42 appearances for Chicago. He’s signed through 2027 after inking a two-year, $20 million contract with the White Sox before this year. He offsets the large salary the team is taking on in acquiring Castillo.
Jones, 28, has been at Triple-A all season after being in Cleveland and Colorado’s organizations while Smith, 23, was the 15th ranked prospect for Chicago. He was hitting .306 at Double-A in 22 games before being traded.
If the White Sox can get the best out of Castillo, he’ll slot in a middle of the rotation that’s recently featured Anthony Kay, Eric Fedde and rookie Noah Schultz. Fedde and Schultz had good outings this weekend against the first place Rays but the latter pitcher is likely to be moved out of the rotation. The White Sox used an opener for him in a 1-0 loss on Saturday.
Castillo’s numbers have been worse while playing in pitcher friendly T-Mobile Park this year — though he’s just a year removed from posting a 3.54 ERA over the course of 180 innings. He also has postseason experience, something none of Chicago’s other starters possess.
The White Sox are still working on acquiring more talent before Monday’s trade deadline. Another starter and/or reliever could be a possibility. Replenishing their catching depth is another possibility with starter Kyle Teel out for most of what’s left of the regular season.
