The Diamondbacks placed Gallen (elbow) on the 15-day injured list Sunday.
The right-hander was scratched from his scheduled start Sunday against the Dodgers due to elbow inflammation and will be out for at least the next couple weeks. The severity of the injury hasn't been disclosed, so it's unclear if Gallen will be ready to return when first eligible in late July. Mitch Bratt was called up to fill the open spot in the rotation Sunday.