Castillo was optioned to Triple-A El Paso on Monday. Castillo was called up a few days earlier to help fill in for Jurickson Profar (COVID-19), but he'll head back down to the minors following Profar's activation. Castillo went 1-for-3 with an RBI and a walk during his brief three-game stint with the Padres.
Castillo's contract was selected by the Padres on Friday. With Drew Pomeranz (shoulder) hitting the injured list, Castillo will join the major-league roster for the first time to provide some depth around the Padres' infield, at least until a fresh bullpen arm is needed. The 25-year-old got off to a 12-for-27 start with Triple-A El Paso to begin the 2021 season, although none of those base knocks left the yard.