Ramirez was injured running out a single during Thursday's game at Cincinnati and removed for a pinch runner.
It's the same problem that caused the 37-year-old Ramirez to miss two starts last weekend.
"It's a recurrence of the calf, and we just have to get this thing fixed. ... The rationale is, if he's better in a week or 10 days, we might as well do this," Dodgers manager Joe Torre said.
The 12-time All-Star is hitting .415 with two homers and 12 RBIs. He reached 1,800 RBI on Wednesday, after recording his 2,500th career hit on April 10 at Florida.
Ramirez is tied with Hall of Famer Mike Schmidt for 14th on the career list with 548 home runs.
Torre informed Ramirez of the move after finding him hitting taking indoor hitting practice before Friday's game against the Washington Nationals.
"He was in the cage hitting today and I told him to pick up a book," Torre joked.
Torre said Ramirez understood the reason the Dodgers weren't waiting to see if the injury improved in a couple of days.
"When he came in to talk to me I said, 'We got to get it better.'" Torre said.
It's the fourth time in his 18-year career that Ramirez has been placed on the DL, and the first time since 2002, when he fractured his left index finger while playing for Boston.
To replace Ramirez on the 25-man roster, the Dodgers recalled outfielder Xavier Paul from Triple-A Albuquerque before Friday's game at the Nationals. Paul was hitting .361 with three home runs and nine RBI in 15 games for the Isotopes.