White Sox Acquire Three-Time All-Star Luis Castillo in Trade With Mariners
· Yahoo Sports
The Chicago White Sox have made their first trade of the 2026 deadline and have finally added to the starting rotation, as fans have been clamoring for.
Late Saturday night, the White Sox sent right-handed pitcher Seranthony Dominguez, outfielder Nolan Jones, and catching prospect Boston Smith to the Seattle Mariners in exchange for right-handed pitcher Luis Castillo.
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Castillo is a 33-year-old veteran and three-time All-Star who is having a down year with the Mariners. He has posted a 3-9 record with a 5.06 ERA this season, but he brings more than 1,500 career innings and a 3.65 ERA since making his MLB debut in 2017.
This was a fit that I highlighted for the White Sox last week. With a current payroll of just over $90 million, the White Sox were in a unique position to take on money in order to acquire the controllable starting pitcher they coveted at the deadline. In this deal, the White Sox will assume the entirety of Castillo's contract, which includes the prorated portion of the $24.15 million he is owed in 2026, another $24.15 million in 2027, and a vesting option worth $25 million in 2028. That option is exercised if Castillo throws at least 180 innings during the 2027 season.
White Sox Can Use Financial Flexibility to Trade for All-Star PitcherThe Chicago White Sox can preserve their farm system and upgrade the starting rotation by taking on Luis Castillo’s contract in a trade with the Mariners.Moving Dominguez also makes the deal more affordable for Chicago. His contract was proving to be a massive overpay, as he struggled out of the White Sox bullpen after signing a two-year, $20 million deal this past winter. Dominguez is owed $10.5 million next season, an obligation that will now be passed on to the Mariners and essentially serve as savings against the $24.15 million owed to Castillo.
Losing Nolan Jones in the deal is negligible for the White Sox. He did not appear to have a path to a roster spot anyway. Dominguez could also prove to be addition by subtraction, especially once the White Sox determine who will replace him in the bullpen.
The real loss for the White Sox farm system is catcher Boston Smith. Smith was the return in the Curtis Mead trade made just before the 2026 season, and in his first taste of professional baseball, he has played in 78 games while posting a .291 batting average and a 1.037 OPS, including 22 home runs across three different levels of the minor leagues. He's only 23 years old, currently plays for Double-A Birmingham, and was recently added to Chicago's list of top 30 prospects.
Is it a loss for the farm system? Absolutely. But that's the price you pay when buying at the trade deadline. For the White Sox, who targeted controllable pitching, it's a small price to pay. Castillo is much more affordable from a prospect standpoint than many of the other controllable starters on the market, especially when considering the upside he offers.
Ultimately, though, this is a multi-year bet by the White Sox on Castillo's potential. He's struggled in 2026, but this is still a three-time All-Star that can dominate the opponent on any given night. He has been a pivotal member of the Mariners' starting rotation for years and also brings valuable playoff experience.
Across six career postseason games, Castillo has posted a 2.25 ERA. If the White Sox can help him return to his previous form, they will have an explosive arm who pairs nicely with Sean Burke and Davis Martin at the top of the rotation, both for the remainder of this season and through at least 2027.
The main questions now are who Castillo replaces in the rotation, who takes Dominguez's spot in the bullpen, and whether the White Sox are done adding to their pitching staff. The organization plans to remain aggressive and has been engaged in talks on multiple fronts for weeks.
Just because the White Sox added Castillo does not mean they intend to sit pat until the trade deadline passes on Monday.