This pitcher has spent time in the Detroit Tigers, Seattle Mariners and Baltimore Orioles organizations.
The 2026 MLB season has officially begun, which means free agents who have gone unsigned may be out of luck for now. While teams always need more players than the 26-man roster that begins each season, it is also true that free agents who did not get a look before Opening Day may not be in the plans for the 30 big league teams.
31-year-old right-hander Luis F. Castillo (not to be confused with the 33-year-old Luis Castillo who is a three-time All-Star on the Seattle Mariners) has chosen to take his talents outside of Major League Baseball. It was reported on Thursday that Castillo has signed with Diablos Rojos del México, a club in the Mexican League.
Castillo had a brief stint with the Mariners last season, making two starts to the tune of a 7.71 ERA. He gave up 12 hits in seven innings pitched, striking out five batters and walking seven. It was not an inspiring stint, and it was his first big league action since 2022 when he appeared in three games out of the bullpen for the Detroit Tigers, pitching 3.2 scoreless frames, surrendering just two hits, no walks, and striking out four batters.
While he never appeared in a big league game for the Baltimore Orioles, that was the last organization he spent time with. The team purchased his contract on May 8 from Seattle, and he appeared in two games for their rookie ball club in the Florida Complex League.
In those outings he pitched 2.2 innings and surrendered one earned run. He struck out five batters and gave up four hits. He was ultimately granted free agency this offseason, where he went unsigned.
A native of the Dominican Republic, Castillo has spent more than a decade in professional baseball. He first signed as a free agent with the Arizona Diamondbacks in 2012, spending time in their minor league system before making his way to the Detroit Tigers via free agency in 2022. His most appearances in a minor league season came in 2019 when he pitched in 43 games for the Advanced-A affiliate of the Diamondbacks. He showed some promise that year, striking out 83 batters in 78 innings and winning all nine of his decisions. His 3.81 ERA was decent, but at that level, wasn’t quite good enough.
At the AAA level, Castillo has made 61 career appearances, posting a 3.62 ERA. He has struck out 65 batters in 74.2 innings pitched, walking 27. While this move outside of Major League Baseball may not close the door entirely on a return for Castillo, it does signify that offers likely were not there this offseason, and with Opening Day upon us, may not have been coming anytime soon.