Reliever Miguel Castro joined the Orioles on Monday from Double-A Bowie for their series opener in Chicago against the White Sox, continuing a bullpen churn caused by an unprecedented short run of starts by their rotation.
To make room on the 25-man roster, the Orioles optioned reliever Logan Verrett to Triple-A Norfolk.
Castro, 22, appeared in two games for the Orioles in his previous stint with the club, walking three and striking out one in two scoreless innings.
Acquired in April from the Colorado Rockies for future considerations, Castro has spent most of his time in the Orioles organization getting on a steady throwing program after two up-and-down seasons for the Toronto Blue Jays and the Rockies.