Walsh posted a respectable .317 on-base percentage and led the Majors (minimum 60 plate appearances) with a 23.8 percent walk rate, but he logged only four hits in 63 plate appearances for a league-worst .085 batting average.
"Anytime you start with Rule 5 picks, it's a tough spot to begin with," Brewers manager Craig Counsell said. "In the end, the way our roster shook out and playing time shook out, we weren't really able to give him consistent at-bats."
The A's paid the Brewers $25,000 -- half of the original fee when the Brewers selected Walsh in December's Rule 5 Draft -- to take him back.
• Right hander Michael Blazek and lefty Chris Capuano, each on the disabled list with elbow injuries to their respective throwing arms, long tossed on Saturday, as they continued making progress in their comebacks. Capuano was pleased with his work from 120 feet, and said he hopes to resume throwing off the mound by the end of the coming week.
• The Class A Wisconsin Timber Rattlers reinstated outfielder Trent Clark from the disabled list on Saturday. Clark, No. 5 on MLBPipeline.com's list of the top Brewers prospects, had missed time with a right hamstring injury.
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.