Lamb, 33, hit .232 with one home run and 32 RBIs this season for the Twins after signing a two-year, $6.6 million contract. He essentially is the Brewers' replacement for Russell Branyan, a fellow left-handed hitter who plays first and third base and remains on the disabled list with a strained right oblique.
But right-handed-hitting Bill Hall and left-handed-hitting Craig Counsell will probably see most of the starts at third base this month, according to Brewers manager Ned Yost.
"He's a bat off the bench, basically," Yost said. "It's been a while since he played. There's a difference between being in uniform and 'playing.' ... But he's got postseason experience, he's been to the World Series, he knows the National League and has been in this division."
Milwaukee made a similar late-season pickup last September, trading with Washington for left-handed reliever Ray King.
Lamb is wearing uniform No. 47. To make room on the 40-man roster, the Brewers designated catcher Lou Palmisano for assignment, but club officials hope to keep him in the organization. Palmisano, who missed much of 2008 rehabbing from left knee surgery, is scheduled to be a taxi-squad player in the Arizona Fall League.
In nine seasons with the Rangers, Astros and Twins, Lamb is a career .277 hitter with 69 homers and 345 RBIs, and he has a .928 fielding percentage at third base. In Milwaukee, he reunited with general manager Doug Melvin, who held that job with the Rangers when Lamb debuted.
Lamb never got comfortable in Minnesota and was designated for assignment after the Twins traded for reliever Eddie Guardado. What happened?
"There is no short answer to that," Lamb said. "I don't know. You would have to ask the manager and the GM over there. My average wasn't where anybody would have liked it to have been, but I had decent RBIs for the time that I played, and defensively, I felt that I was more than adequate. People will make judgments on that. I was quite pleased with what I was doing out there.
"I don't know why I didn't get another chance. I don't know why it went down the way that it did."
After Lamb's exit, Twins manager Ron Gardenhire was not exactly complimentary.
"The energy level wasn't what we expected," Gardenhire said at the time. "He's more of a veteran, laid-back guy, and we play at a different level. ... He's an off-the-bench kind of guy, that's what it looked like to me, and we were looking for a little different thing."
Lamb was asked if he had a response to those comments.
"I am disappointed that he felt that way," Lamb said. "I didn't feel that was the case. As I stated when reporters asked me about my laid-back approach, if it would have been communicated to me that it was a problem, I would have tried to do something about it.
"No one ever said anything to me. How was I to know there was a problem? Nobody wants to get fired and find out later that it was for something that could be changed."
The Brewers have no shortage of players to man the hot corner. Besides Counsell and Hall, they also have September callups Joe Dillon (who made one start at third for Milwaukee earlier this season), Mat Gamel and Vinny Rottino.
Lamb tried to stay sharp during his 11-day layoff, but it was difficult. All of his offseason workout partners are still playing baseball, and his wife, Teresa, is pregnant. The couple is expecting their third child in early October.
"It's good to be back out on a field," Lamb said. "It's nice to get back out there, get my legs underneath me, take some grounders and take batting practice. It's definitely more fun being out here than not."