The Blue Jays were in need of a starting pitcher because of a doubleheader against the Yankees earlier this week and another off-day not coming until Thursday.
"I think we're just going to need one start," Blue Jays manager John Gibbons said. "That's the way it turned out with the doubleheader and then an off-day. He has been up here, he's a seasoned vet, he had some good starts for us, and he was doing fine down there. Everything kind of fell in line."
Wang got off to a relatively good start with the Blue Jays when he went at least 6 1/3 innings in each of his first three outings. The Taiwan native then struggled and lost his job after allowing 13 runs over just 3 1/3 innings in a pair of subpar starts.
The Blue Jays will have to open up a spot on their 40-man roster before Wang can officially be promoted from Triple-A Buffalo. A spot on the 25-man roster is already available because left- hander Aaron Loup was placed on the paternity list Friday afternoon.
Toronto could opt to find a player to designate for assignment, but a more likely scenario would be to transfer one of their injured players to the 60-day disabled list. Outfielder Melky Cabrera isn't expected to return this season, while right-hander Josh Johnson also could be done for the year, making both candidates to be transferred to the 60-day DL.
The 33-year-old Wang posted a 3.18 ERA in eight starts this season for Triple-A Buffalo. The Blue Jays opted to go with a veteran arm instead of choosing left-handed prospect Sean Nolin, who made a spot start earlier this year against the Orioles.
Gregor Chisholm is a reporter for MLB.com. Read his blog, North of the Border, and follow him on Twitter @gregorMLB. This story was not subject to the approval of Major League Baseball or its clubs.