Freeman had played 128 of 142 games for the Braves through Monday's 4-1 loss, with just one day off in the month of August. Over his last 35 games, Freeman has struggled a bit at the plate, batting just .205 with six home runs, five doubles and 19 RBIs.
Since the start of August, Freeman's batting average has dropped more than 20 points.
"Just a day off," said Braves manager Fredi Gonzalez. "Plus, I don't think we can leave Milwaukee without putting Overbay or [Eric] Hinske in the game."
After spending most of the season with the D-backs, Overbay signed a Minor League contract with the Braves last month and joined the big league club Sept. 1. The veteran got his first Braves hit Monday night, a seventh-inning pinch-hit single.
For Overbay, the start was his first with the Braves and just the 22nd of the season, as the 35-year-old has been utilized primarily as a pinch-hitter.
"It's double-fold," Gonzalez said. "Give Freddie a day, and also give Lyle three at-bats, four at-bats. Let him get some playing time over there."