"[Nolin] is not going to be part of the choices we have to make," Counsell said.
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Nolin, claimed off waivers from the A's on Feb. 22, last pitched on March 14 against the Dodgers. He has yet to undergo an MRI scan, Counsell said.
Nolin was one of three left-handers vying for a spot in the bullpen alongside incumbent Will Smith. The others -- Chris Capuano and Franklin Morales -- are both non-roster invitees, and Nolin had a further advantage in that he was out of options.
"We thought [Nolin] was going to get past it," Counsell said, "but it was smart to be more conservative with this."
Besides Barrios and Nolin, Brewers outfielder Rymer Liriano will also open the season on the DL. He suffered facial fractures when he was hit by a pitch Sunday.
"It can change so fast," Counsell said. "The last couple of days, we've had changes to the decisions we're going to make, the different ingredients that go into the decisions. That's why you wait to make decisions, because a day changes everything."
• Free agent right-hander Kyle Lohse will throw off the mound for scouts in the Phoenix area on Wednesday, MLB Network's Jon Heyman reported. Lohse was 5-13 with a 5.85 ERA for the Brewers last season.
He has some experience with signing late. In 2013, when Lohse was attached to Draft compensation, he did not sign his three-year contract with the Brewers until March 25.
Adam McCalvy is a reporter for MLB.com. 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.