White Sox add former All-Star Luis Castillo in deadline deal with Mariners

Ahead of the trade deadline, the Chicago White Sox completed a high-profile transaction, sending reliever Seranthony Domínguez, outfielder Nolan Jones and prospect Boston Smith to the Seattle Mariners for right-hander Luis Castillo. The move follows a dramatic turnaround for Chicago, which went from a 102-loss campaign last year to leading the American League Central. Castillo, a two-time All-Star who finished fifth in Cy Young voting in 2023, has struggled this season, posting a 5.06 ERA and a 3-9 record over 20 starts.

The White Sox hope his upside will bolster a rotation that currently ranks 16th in MLB ERA at 4.29, according to FanGraphs. Chicago will also take on the remaining money on Castillo’s contract, with a $22.75 million salary slated for next year and a vesting option that could extend through 2028 if he logs 180 innings in 2027. Seattle acquires Domínguez, who has a 3.99 ERA in 43 appearances, as they sit four games below.500 but remain within striking distance in the AL West.