Jimenez twisted his ankle in a parking lot at his apartment complex on Wednesday.
"We were looking at it today and it's pretty puffy, taped up," Orioles manager Buck Showalter said Friday. "We were hoping it would resolve somewhat today. Did not."
The move is retroactive to July 6, the day after Jimenez made his last start.
Very little has gone right this season for Jimenez after he signed a $50 million, four-year deal during the offseason. He's 3-8 with a 4.52 ERA overall and 1-4 with a 5.79 ERA at home.
Jimenez appeared to be back on track after he gave up an unearned run in eight innings against Texas on June 30. But he didn't last long in his last start, walking six against Boston before being yanked after 3 2-3 innings.
The ankle sprain is not a first for Jimenez.
"He had it in 2012," Showalter said. "The only reason I asked him that is I wanted to know how quickly it healed. Anybody who's rolled their ankle, they know once you do it once, it kind of falls on a similar pattern. And he did it pitching. They shut him down the last two or three starts in 2012."
By being placed on the DL on Friday, Jimenez gets the benefit of being inactive at the same time the Orioles are on break for the All-Star Game.
"If it wasn't for the All-Star break, we might wait a couple days," Showalter said. "But it's also the same ankle as 2012, and with ankles, I've learned that you kind of take a look at the history with them. It's a lot weaker every time you put it in peril."