The team made the move retroactive to Thursday and called up pitcher David Hale from Triple-A Albuquerque on Saturday.
Hundley has been experiencing concussion symptoms since he was hurt Wednesday. He is hitting .227 with one home run in seven games.
He said after limiting his sprints and swings in the batting cage he felt a "little woozy." He then decided to "shut it down" and "take it back a notch" to give himself more time to recover.
Hale was 0-1 with a 1.50 ERA in six innings at Albuquerque after he strained his right hamstring in spring training. He went 5-5 with a 6.09 ERA in 78 1/3 innings with Colorado last season.