"It's a significant strain," Dodgers manager Joe Torre said. "I got a call when I was on my way here. So, that's why it wouldn't go away, because it was more than something mild, I guess."
The Dodgers activated 41-year-old catcher Brad Ausmus from the 60-day disabled list in Ramirez's stead. Ramirez, 38, was put on the disabled list retroactive to Saturday.
An MRI on Tuesday reviewed by team doctor Neal ElAttrache revealed the strain, which is in Ramirez's soleus -- a different calf muscle from the one that was strained when he went to the DL on April 23, the gastrocnemius. Ramirez's most recent DL stint, which ended five days ago, was because of a hamstring strain in the same leg.
"We know this specifically because we got MRIs on both [calf muscles]," Dodgers athletic trainer Stan Conte said. "I think you have to think it's somehow related. All three of his injuries on the same side, so you think there's some sort of relationship there."
Batting .317 with eight home runs and 39 RBIs, Ramirez has played only two games this month, the first two after the All-Star break. The Dodgers have looked to Ramirez's two previous returns from injury with optimism, making Tuesday's news a letdown in the midst of a five-game losing streak.
"I think this was a big disappointment, I know it was a big disappointment," Torre said. "By virtue of the fact that we just got him back off the list and really nothing happened other than it was worse than first thought.
"I talked to him every day, but not much to say. I just said, 'At some point, we'll get you back.'"
Xavier Paul will continue to see most of the time in left field, with Jamey Carroll seeing time against left-handers. The Dodgers carried three catchers Tuesday night for the middle of a three-game set with the Giants at Dodger Stadium, but by Thursday, Torre said the team would likely call up an outfielder in place of a catcher.
"That's what we're talking about now," Torre said. "We didn't really expect this to happen so we weren't really prepared to say [here's what happens] if he goes on the DL because it didn't seem like that was going to be the case."
That outfielder would be a temporary fill-in for Reed Johnson, who could return this weekend from a lumbar strain. Double-A center fielder Trayvon Robinson's name did not come up, Torre said. Robinson is batting .296 with eight home runs and 37 RBIs and is on the 40-man roster.
At Triple-A Albuquerque, Jay Gibbons could be a possibility. Gibbons is batting .322 with 15 home runs and 65 RBIs.
"He's doing very well," Torre said of Gibbons. "We haven't had a lot of conversations, so we really haven't settled on one person, but his name definitely came up."
Also in Albuquerque is Jamie Hoffman, who's hitting .314.
The Dodgers have room on their 40-man roster, but because of Johnson's imminent return, they likely won't call up anyone for whom starting the arbitration clock is a worry.
"You have to be careful on who you add," Torre said.
Evan Drellich is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.