The Rockies recalled Halvorsen from Triple-A Albuquerque on Thursday.
Halvorsen wasn't able to win a spot on the Opening Day roster but will get a look now after yielded just two runs with a 12:5 K:BB in his first 10 innings at Albuquerque. His stay could be a short one, as Halvorsen is a good bet to be sent back down when Jimmy Herget returns from paternity leave.