The Brewers recalled Lopez from Triple-A Colorado Springs on Wednesday.
Lopez will give the Brewers some length out of the bullpen after Milwaukee relievers combined to cover 10 frames in extra-inning affairs the past two days. A former top starting pitching prospect in the organization, Lopez has since been converted to a full-time bullpen role after faltering in the high minors over the last two seasons. He's unlikely to be in line for an extended stay with the big club.