Castillo was optioned to Triple-A Toledo after Thursday's extra-inning loss to the Guardians, Evan Woodbery of MLive.com reports.

EDGE Analysis

The 27-year-old was called up from Triple-A over the weekend and delivered two scoreless frames in two appearances during his first taste of the big leagues. Castillo will return to Toledo, where he has a 1.56 ERA, 1.20 WHIP and 32:10 K:BB across 34.2 innings.