Castro was sent to Triple-A Albuquerque on Saturday, prior to the Rockies hosting the Arizona Diamondbacks in the third game of a four-game series. Yohan Flande was called up from Triple-A and added to the 40-man roster in a corresponding move.
With Flande’s call-up, the Rockies now have a full 40-man roster.
The 21-year-old Castro has a 12.27 ERA over his last seven games, giving up nine hits and five runs in 3.2 innings while striking out just two batters.
After pitching against the Chicago Cubs on April 17, Castro began to suffer from right shoulder inflammation and was subsequently placed on the 15-day disabled list with the injury.