Lawrie becomes the 15th Blue Jays player this season to hit the DL. A corresponding roster move will not be announced until the club returns to Toronto on Friday.
The 22-year-old had been optimistic about avoiding a prolonged absence from the lineup, but when the injury failed to show noticeable signs of improvement over the past few days, the club was left with no choice.
"Just to make sure there's no potential for a recurrence or a reaggravation of the injury," Blue Jays manager John Farrell said of the roster move, which is retroactive to Aug. 4. "This way it gives him another eight days to address the situation, let the symptoms completely clear up, rather than risking further injury if he were to get back into a game too soon."
Lawrie felt a pinching sensation in his rib cage during an at-bat against Oakland on Aug. 3. He was removed from the game after the plate appearance and originally was listed as day to day.
In the days that followed, Lawrie received regular treatment with the hopes of getting back into the lineup. He began throwing again on Wednesday and went through some dry swings Thursday, but he is not yet to the point of being able to go through full baseball activities.
"I think it will help in the sense that he comes in every day wondering if today is the day," Farrell said. "If he knows that he's got eight more days in which he's ineligible because of the DL, hopefully that relaxes his mind enough, and maybe that promotes additional healing.
"I'm not trying to get too deep, but if he knows that he has a defined period of inactivity coming up, he can focus solely on some of the movements and strengthening to help the oblique get back to normal."
Prospect Adeiny Hechavarria will continue to start at third base during Lawrie's absence. Farrell indicated prior to his club's series finale against Tampa Bay that the Blue Jays likely will add an eighth reliever to the bullpen, instead of making a roster move for an additional position player.
Lawrie is batting .282 with nine home runs and 40 RBIs in 100 games this season. He has 32 extra-base hits and a .742 OPS while walking 22 times in 397 at-bats.