The Orioles outrighted Castro to Triple-A Norfolk on Monday.
Castro lost his spot on the 40-man roster without having ever made an appearance at the big-league level for the Orioles, who claimed him off waivers from the Guardians on Sept. 3. He spent the entire final month of the season at Norfolk, where he logged a 2.89 ERA and 1.98 WHIP in 9.1 innings.