Halladay allowed two hits, struck out one and walked one. He pitched for the Blue Jays from 1998-09, then was traded to the Phillies.
"Just being in the game again is fun," said Halladay, who led the NL with 21 wins last season. "You can throw as many bullpens and you want but it's always different once you get out there. It's always fun getting back out there."
Carlos Ruiz had a two-run double in the second inning off Blue Jays starter Jo-Jo Reyes, and Placido Polanco had a two-run single off Carlos Villanueva in a three-run fourth. Mike McCoy doubled in the seventh to end a 24-inning scoreless streak for the Blue Jays.