The team had been hoping to avoid making the move, but Muncy needed more time to recover after getting hurt in last weekend's game atPhiladelphia.
"It was a low-grade strain, tried to go out there and run and still felt it," manager Dave Roberts said. "He can still hit, but we'd have to [pinch] run for him."
The move was retroactive to Tuesday, so Muncy will be eligible to come off the IL in time for the Dodgers' series at home againstHoustonstarting June 23.
"I love playing," he said this week. "I don't like sitting. It kills me."
Muncy has struggled offensively this season, hitting .191 with 18 home runs and 45 RBIs in 60 games. It's his first time on the IL this season and fourth time in his career.
Chris Taylor and Michael Busch figure to split time at third base while Muncy is sidelined. Busch was recalled from Triple-A Oklahoma City on Friday for his second stint with L.A. this season. He was 4-for-19 with 2 RBIs in seven games the first time.