The 29-year-old Ottavino is 1-0 with three saves in 10 appearances this season. He has allowed three hits and no runs with 13 strikeouts in 10 1-3 innings.
Rondon has made one big league appearance, tossing one inning with St. Louis against the Los Angeles Dodgers last season. He has allowed a run in 6 2-3 innings at Albuquerque this season.
The Rockies also reinstated right-hander David Hale, who had been out with a strained oblique, from the 15-day DL and optioned him to Albuquerque.