"I think Sam has a really good arm. There's something in there for sure," Brewers manager Craig Counsell said. "He's had success at the Major League level. At this point, we need to be able to count on that spot. We need to be productive. Sam was just having trouble throwing strikes."
The Brewers have taxed their bullpen, because the team's starters have averaged just better than five innings per outing. Their other left-hander, Chris Capuano, had been more productive (4.50 ERA in 10 appearances).
Guerra was already on the 40-man roster, so Freeman's departure created an opening there.
The Brewers removed right fielder and leadoff hitter Domingo Santana from the starting lineup minutes before Jimmy Nelson's first pitch on Monday because of tightness behind Santana's right shoulder. He could be back in the starting lineup as soon as Saturday, Counsell said.
"I don't think it is serious," Counsell said. "He had something similar to his left shoulder in Spring Training that [lasted] a couple of days. I don't think it is serious at all."
Santana hit his first career leadoff home run in Sunday's win over the Marlins.
Adam McCalvy has covered the Brewers for MLB.com since 2001. Follow him on Twitter @AdamMcCalvy, like him on Facebook and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.