Castano (0-2) took the loss in Game 1 of Saturday's doubleheader against the Nationals after allowing two runs on one hit with one strikeout and two walks while recording only one out.
Castano retired one of the four batters he faced while delivering only 10 of his 23 pitches for strikes, leading to the quick hook. The 25-year-old covered 10.1 innings with a 4.35 ERA across his first two outings before Saturday, and he could make another start next week if the Marlins don't return any starters from the injured list.