The Seattle Mariners trade starting pitcher Luis Castillo to the Chicago White Sox ahead of the MLB trade deadline, according to multiple reports. The teams complete the deal for three players: right-hander Seranthony Domínguez, outfielder Nolan Jones, and catcher prospect Boston Smith. One outlet also reports that cash considerations are included as part of the exchange. The reports characterize the move as a roster shake-up by Seattle, while adding pitching and infield depth for Chicago as the White Sox seek to strengthen their rotation. The Mariners send Castillo, a key member of their starting staff, to the White Sox in exchange for the younger talent package. The deal shifts prospects back to Seattle with Jones and Smith providing position-player upside, and Domínguez offering bullpen value. The reports do not indicate that any additional players are exchanged beyond the three prospects and the reported cash component. Overall, the coverage aligns on the names involved and the core structure of the trade: Castillo for Domínguez, Jones, and Smith (plus cash considerations).