Luis F. Castillo signed with the Mexican League's Diablos Rojos De México.
Most deals for players heading to Mexico have clauses that allow them to depart if they get an offer from an affiliated club. Castillo made his MLB debut with the Detroit Tigers in 2022 with three appearances before pitching in Japan's NPB with the Chiba Lotte Marines in 2023 and the Orix Buffaloes in 2024.
Over those two NPB seasons, Castillo tossed 143 1/3 innings with a 3.01 earned run average. He returned to North America by signing a minor league deal with the Seattle Mariners ahead of the 2025 season and was added to the roster in early April, making two starts and allowing six earned runs in seven innings.
In May 2025, Castillo was designated for assignment and claimed by the Baltimore Orioles. He was outrighted off the 40-man roster during the summer and became a free agent at season's end.