The Blue Jays purchased Lawrie's contract from Triple-A Las Vegas following a 7-6 loss to Tampa Bay on Thursday afternoon.
Lawrie will immediately move into the starting lineup at third base with slugger Jose Bautista sliding back to right field.
"We felt like, one, he was ready," Toronto manager John Farrell said. "Two, we wanted to get in a position where he joins us on the road.
"Finally, this is a guy that we've had a lot of expectations on. That's not to create more of a hysteria situation, than the attention that's going to follow him, but he has done everything we've asked at Triple-A."
Lawrie was on the verge of being promoted to the Major Leagues in late May before he fractured his left hand. The native of Langley, British Columbia, then went through a grueling month-long rehab before re-joining the 51s in mid-July.
It took Lawrie some time to find the same type of success he was experiencing prior to the injury, but he appears to be heading to the Majors on a hot streak.
Lawrie was hitting .348 (24-for-69) in 17 games since being activated from the disabled list. He also put in some extra work in recent days with roving infield instructor Mike Mordecai as the two looked to get the 21-year-old back into his pre-injury form at third base.
The Blue Jays felt it was important to get Lawrie some experience at the Major League level before rosters expand in September. That's the same time of year where competition around the big leagues drops because of the arrival of Minor Leaguers and teams playing out the string.
This promotion will provide Lawrie with a larger sample size of games for the club to evaluate his talent. General manager Alex Anthopoulos also believes the club has done everything it could to prepare his young third baseman for the next step.
"We try to put these players in the best position to have success when they come up here," Anthopoulos said. "You know you're not going to be 100 percent sure. Like I always say, the likelihood, with all players, they're likely going to have to go back down. But at least you want to do the best you can developmentally to prepare them for being up here.
"Hopefully now it's one of those things with Brett where he can stay up here for the entire year."
Travis Snider was optioned to the Minor Leagues to make room for Lawrie on the 25-man roster. The decision on who was going to get demoted ultimately came down to Snider and rookie outfielder Eric Thames.
Both players had been struggling in recent games, with Snider batting just .136 (6-for-44) in his past 11 games while Thames is hitless in his last 21 at-bats.
"Player performance is really what it came down to," Anthopoulos said. "Both players we see as having a chance to be here long term and have a chance to be part of this core. Ultimately, either decision we would have made, neither player would have been happy or want to be sent down.
"When you look at the numbers and the performances to date they both haven't done all that great the last week or so ... but on the season, overall, Eric has played a little bit better."
Edwin Encarnacion was the obvious candidate to lose playing time earlier this season when Lawrie appeared ready for the Majors. The 28-year-old designated hitter has excelled at the plate recently, though, and the club didn't want to take away any of his at-bats.
Encarnacion entered play Thursday hitting .364 with a .449 on-base percentage and a 1.047 OPS since July 7. He's tied for third in the American League over that span with nine doubles and fourth in runs scored with 18.
Toronto has a 2012 club option on the Dominican native, which it can exercise at the end of the season for $3.5 million. That option played a role in the Blue Jays wanting to ensure he receives regular playing time, in an effort to monitor whether he is part of their plans for next year.
"This isn't about giving playing time to someone who isn't going to be here for the long term, whether it was a Juan Rivera before or a Corey Patterson," Anthopoulos said. "Eric Thames is going to continue to get the at-bats and Edwin Encarnacion will continue to get bats at DH. He has a club option on next year that we still have two months of the season -- [we] want to continue to evaluate him."