The Mariners have signed right-hander Luis F. Castillo to a minor league contract and invited him to big league camp this spring, Jon Heyman of the New York Post reports. The 29-year-old Castillo — obviously not to be confused with the eight-year MLB veteran of the same first and last name currently in Seattle’s rotation — pitched briefly with the Tigers in 2022 and has spent the past two seasons in Japan.
The younger Castillo has pitched 3 2/3 shutout frames in the majors, yielding only two hits and no walks with four strikeouts for Detroit in that ’22 cup of coffee. He carries a career 1.93 ERA in 18 2/3 Double-A frames and a 3.28 ERA in 60 1/3 Triple-A innings spread across two seasons. The Tigers outrighted him off their 40-man roster following the 2022 season, and he elected free agency before going on to sign with Nippon Professional Baseball’s Chiba Lotte Marines in Japan.
Castillo pitched well with the Marines, logging 49 innings with their big league squad and recording a 3.12 ERA with a sub-par 17% strikeout rate but a microscopic 1.5% walk rate. He faced 200 batters that season with the Marines and issued only three walks (plus another two hit batsmen).
Castillo parlayed that impressive showing into a bigger look with NPB’s Orix Buffaloes. As with the Marines, he pitched quite well. Castillo pitched 94 1/3 innings out of the Buffaloes’ rotation (15 starts) and notched a 2.96 ERA with an improved 19.6% strikeout rate. The absurd walk rate he demonstrated a year prior unsurprisingly proved impossible to sustain, but his 4.8% walk rate was excellent nevertheless.
Whether the newly signed Castillo will serve as rotation depth or compete for a spot in the bullpen isn’t clear. The Seattle rotation is stacked with the presence of the other Luis Castillo, George Kirby, Logan Gilbert, Bryce Miller and Bryan Woo. Depth options like Emerson Hancock, Jhonathan Diaz and Blas Castano are all on the 40-man roster, while well-regarded prospect Logan Evans pitched quite well in Double-A last season and could be ready for a big league look this summer.