Luis Castillo’s season with the Chicago White Sox may already be over.
The White Sox put the former Seattle Mariners right-hander on the 15-day injured list Thursday because of a right shoulder impingement, a move that likely shuts him down for the year. It’s the latest blow in a rough run since Chicago landed him in the four-player trade that sent reliever Seranthony Domínguez, outfielder Nolan Jones and catching prospect Boston Smith to Seattle.
Castillo has not found his footing with the White Sox. In nine appearances, he has posted an 8.42 ERA and a 1.81 WHIP across 31 innings.
That ERA is the highest in MLB among pitchers who have thrown at least 30 innings since he was dealt on Aug. 2.
Chicago tried to squeeze one more start out of him by using an opener against St. Louis on Sept. 12, but the plan didn’t hold.
Castillo gave up three runs in 2 2/3 innings, then was sent to the bullpen. His next two outings came in relief, including Tuesday against Kansas City, when he allowed four runs in one inning.
The White Sox brought Castillo in hoping he could be the arm that pushed their rotation toward the postseason for the first time since 2021. Even with his struggles, the club punched its playoff ticket Thursday afternoon and sits in the American League’s final wild-card spot at 81-77, 3 1/2 games ahead of Houston. Chicago is also only a half-game behind Cleveland in the AL Central.
The injury designation means Castillo is out at least through the AL Division Series, though he would still be eligible if the White Sox make it to the ALCS.
Castillo, a native of Bani, Dominican Republic, spent parts of five seasons in Seattle after the Mariners’ 2022 trade deadline blockbuster helped end their 21-year playoff drought. In 126 career appearances for the Mariners - 123 of them starts - he went 43-40 with a 3.69 ERA over 718 innings. He ranks 10th in franchise history with 719 strikeouts.
His contract still has money attached, too: Castillo is due $24.15 million next season in the final year of his deal, along with a $25 million vesting option for 2028 if he reaches 180 innings next season.
Seattle’s return has worked out well so far. Domínguez has a 3.18 ERA and 1.15 WHIP in 23 games since arriving, and over his last eight outings he has given up just one earned run while striking out 13 and walking three. Smith has also climbed quickly, hitting nine homers in 33 games at Double-A Arkansas after the trade, finishing the minor league season with 31 home runs across three levels, and he is slated to play in the Arizona Fall League next month.
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