 With Houston in 2012, he posted a 7–9 record with a 4.83 ERA, 98 strikeouts, and a 1.45 WHIP in 104 innings.Happ was traded to the Toronto Blue Jays on July 20, 2012, along with Brandon Lyon, and David Carpenter, for Francisco Cordero, Ben Francisco, Asher Wojciechowski, David Rollins, Joe Musgrove, Carlos Pérez, and Kevin Comer.Happ worked as a reliever for the Blue Jays until the demotion of Brett Cecil allowed him to be promoted to the vacant starting role.