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."
Halladay limited the Blue Jays to two singles, striking out one and issuing one walk.
"There's a couple things I want to try," Halladay said, "but for the most part, the biggest thing is just getting back comfortable. ... There were times today where I felt good, felt good about the pitches I made, and there were times I felt a long way from where I need to be. Overall, it's about what I expected."
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. They added two more in the ninth off Scott Mathieson on Jon Diaz's double, Eric Thames' triple and a sacrifice fly.
Toronto finished with eight hits, matching the combined total in two losses to Detroit in the first two spring games, but the Blue Jays also committed five errors.
NOTES: Toronto RHP Kyle Drabek was scratched from Monday's start due to a stiff neck. He is scheduled to start Saturday against Detroit. ... LHP Jesse Carlson will sit for several days with inflammation in his left shoulder. RHP Alan Farina replaced him in the Blue Jays' bullpen. ... Toronto OF Travis Snider, who pulled an upper ribcage muscle playing golf before spring training, took batting practice Monday and likely will play next weekend. ... Michael Weiner, head of the players' union, met with the Blue Jays before the game. He said he expects there will be one or two formal bargaining meetings with the owners during spring training "and we'll begin in earnest, I think, when everybody's back and the season begins." ... Cliff Lee is scheduled to start for the host Phillies against Detroit's split squad and Andy Oliver at Clearwater. Jacob Turner and the other half of the Tigers' squad will face visiting Toronto and Ricky Romero at Lakeland.