White Sox acquire Luis Castillo from Mariners in multi-player trade

Chicago traded right-hander Seranthony Domínguez, catcher/outfielder Boston Smith and outfielder Nolan Jones to Seattle for right-hander Luis Castillo. The deal gives the White Sox a pitcher they hope can improve by 2027 and provides the Mariners with a veteran reliever and two position-player prospects. Boston Smith, a former sixth-round pick out of Wright State, has progressed quickly through the minor leagues, reaching Double-A in July and posting a .306/.485/.667 line in 23 games. He has shown power but continues to adjust to higher-level off-speed pitching and may also be developed as a catcher or outfielder. Outfielder Nolan Jones, who saw limited major-league action with Colorado in 2023, spent the season in Triple-A, hitting .281/.394/.482 against right-handed pitching. Seattle hopes he can add depth to a right-field position that has been a relative weakness. The Mariners also added veteran right-hander Seranthony Domínguez, who is effective against right-handed batters, to bolster their middle-relief corps. Luis Castillo, who carries $30 million through 2027, struggled this season as hitters attacked his fastball and slider, prompting Seattle to move on from the contract. Chicago will evaluate whether adjustments can raise his performance above replacement level for the 2027 season.