Two days after the Lorenzo Cain fiasco (his agent had tweeted "Welcome to the show!" when he was only being brought to Milwaukee in case Gallardo was DL'd), the Brewers decided to put Gallardo on the DL anyway, activating Doug Davis, who is not scheduled to pitch until Friday.
Apparently they realized that while Gallardo's injury delayed their need to make a decision on who Davis would replace in the rotation, they still faced the issue of who Davis would replace on the roster if Gallardo wasn't put on the DL.