Colorado optioned Shook to Triple-A Albuquerque on Sunday.
Shook joined the Rockies on June 1 and appeared in three games, allowing two runs while posting a 3:0 K:BB over 3.2 innings. He's headed back to the minors in favor of lefty reliever Sammy Peralta, who was called up from Albuquerque to take Shook's bullpen spot.