Crawford, who made his Major League debut earlier this season, has posted a 4.50 ERA in five relief appearances for Toronto. To make room on the 25-man active roster, right-hander Joel Carreno was optioned to Double-A New Hampshire.
The 25-year-old Crawford will provide the Blue Jays with the luxury of having a third lefty to use out of the bullpen. That was considered a key addition for upcoming American League East series against the Rays and Yankees and an Interleague matchup against the Mets.
"When you look at the next four series, Tampa being twice, we're going to face lineups that have four and five lefties in the lineup, so that's where Evan comes back into the mix," Blue Jays manager John Farrell said.
Crawford opened the season with New Hampshire, where he recorded three scoreless appearances. He also has appeared in four games with Las Vegas, posting a 7.56 ERA without a decision.
Carreno began the year as Toronto's No. 5 starter, but was demoted to Triple-A after just one start. He returned in early May and has posted a 4.50 ERA in five games.
"The fact that we used Joel in two of the last three days," Farrell said of the reasoning behind the club's decision. "He was likely going to have a couple of days down just to recover, so it was kind of a natural fit to make the change.
"He is going go back down and start."