Ramirez tweaked the hamstring on a Billy Hamilton bunt Tuesday in Cincinnati.
He missed about a month during the first half of last season with a strained left hamstring. In 2013, Ramirez had two separate month-long stints on the DL because of left knee injuries.
"When you get old, it's not easy," said the 36-year-old, who announced in Spring Training he would retire at year's end. "That's why it's tough to play every day when you get up there in age. That's what you've got to work on. Baseball terms, I have a lot of miles on my body. So you've got to just keep working."
Hector Gomez started in Ramirez's place on Saturday, and the Brewers also have utility man Jason Rogers available to play third, though Rogers had a difficult day in the field during his only start at the position.
Adam McCalvy is a reporter for MLB.com. Follow him on Twitter at @AdamMcCalvy. This story was not subject to the approval of Major League Baseball or its clubs.