Villanueva will not make his scheduled start against Tampa Bay on Tuesday.
Left-hander J.A. Happ, inserted into the rotation following Friday night's game in Oakland, will be moved into Villanueva's spot for now.
Villanueva (6-1, 3.19) won his first four decisions as a starter. He lost his last outing at Seattle.
Toronto recalled right-hander Chad Jenkins from Double-A New Hampshire on Sunday. Jenkins, the Blue Jays No. 1 choice in the 2009 amateur draft, was 5-9 with a 4.56 ERA at Double-A. He has not appeared in the major leagues.