The Rockies designated Peralta for assignment Sunday.
Peralta will give up his spot on the 40-man roster to veteran right-hander John Brebbia, whose contract was purchased from Triple-A Albuquerque on Sunday. Before he was optioned to Triple-A on June 12, Peralta coughed up three earned runs on three hits and two walks over 2.2 innings in two appearances out of the Colorado bullpen across three stints with the big club this season.