The Brewers placed Zastryzny on the 15-day injured list Thursday due to left elbow tendinitis.
Zastryzny gave up his first earned run of the season during his last outing Wednesday, throwing 38 pitches while serving as Milwaukee's opener. He'll now be held out of action for at least the next two weeks as he manages an elbow injury. Janson Junk will come up from Triple-A Nashville to fill the open spot in the Milwaukee bullpen.