Castellanos joined the Astros as a July 2 signing from Mexico in 2015. He debuted in rookie ball the next year and eventually climbed up the minor league ladder to the majors. Castellanos has pitched to an impressive 2.92 ERA in 216 minor league innings, also adding 205 strikeouts against just 46 walks.
Unfortunately for Castellanos, the 22-year-old’s initial taste of MLB action last season didn’t go well. He yielded eight earned runs on 12 hits (including two homers) and five walks in 10 2/3 innings, though he did post 12 strikeouts.