Valdez was recalled from Triple-A Buffalo on Wednesday, Gregor Chisholm of MLB.com reports.
He'll fill the vacancy created when Leonel Campos (groin) was placed on the disabled list. Valdez has been solid as a swingman for the Bisons this season, logging a 3.67 ERA and a 29:7 K:BB in 34.1 innings pitched, so he'll head to the majors to provide a fresh arm in Toronto's bullpen. He seems to be destined for a long-relief role.