But before Happ completed his second full season with the Phillies, he was traded to the Houston Astros; Happ switched uniforms again in 2012.
Although he has shown brief flashes of his '09 form, Happ has been largely inconsistent (and injury-plagued) since leaving Philadelphia. He returned to Citizens Bank Park last night with a 4.77 ERA in 83 starts since he was traded away, and in the last three seasons, only two major league starting pitchers had a higher ERA than Happ's.
But working against a Phillies lineup that has been anything but consistent in the season's first month, the inconsistent Happ looked like his former self.
Happ tossed five shutout innings and got all he would need when Jose Reyes led off the game with a home run against Kyle Kendrick as the Blue Jays beat the Phillies, 3-0.
Happ, making his first start of the 2014 season, held the Phillies to three hits - all singles - and got a ground-ball out or strikeout against nine of the 21 batters he faced.
"Happ pitched one heck of a game," Phillies centerfielder Ben Revere said. "He hit his spots. We got runners in scoring position, but couldn't really do much. It's one of those games where you put the ball in play but it didn't go our way too well."
Relegated to relief work after beginning the season on the disabled list with a sore back, Happ was effective, if not dominant.
He allowed a leadoff single to Revere to begin his night, then erased Revere two batters later by picking him off first base. In the second, Happ walked a pair of batters, but left the bases loaded by getting Kendrick to bounce out to second base to end the inning.
"It felt great," Happ said. "I didn't feel real comfortable at first, but felt better as the game went on. I was trying to focus on getting strike one."
Kendrick was just as effective - at least after the second inning. Kendrick went seven and put zeros on the scoreboard in the final five to register his fourth quality outing in six starts this season.
But he gave up two in the first - on Reyes' homer and Juan Francisco's perfectly placed, bloop run-scoring single to left two outs - and the Phillies' offense was incapable of saving him.
"He gave us a chance," Phillies manager Ryne Sandberg said of Kendrick, "keeping it to three runs."
Kendrick, who has a 3.58 ERA in six games, ran his career-high losing streak to eight games. Kendrick hasn't won a game since Aug. 11, 2013.
But the Phillies offense, and not Kendrick, is to blame. Kendrick has received 2.39 runs of support per nine innings in the 13 starts he's made in the losing streak. Entering yesterday, Kendrick's run support was the fifth lowest in the big leagues during that span.
"He's pitched better than his record shows," Sandberg said. "It doesn't reflect on how well he's pitched. He's just got to keep going out there and battling. He did a great job after the two innings and gave our bullpen a needed rest."
The Phils were so desperate for runs, they tried to summon one from New York.
After Marlon Byrd led off the sixth with a triple, Ryan Howard followed with a fly ball to right and Byrd tagged and made a beeline for home. He was called out on the play. Sandberg asked the umpires to call to the league offices for confirmation of their call on the play at the plate. The play stood as called, and the offense never located home plate again.
"That's the way baseball goes," Revere said. "Luckily, we just get it out of the way early, and, come late in the season, we need those big hits and big runs and we're going to come through."
The Phillies, winners of eight of their previous 12 entering the night, fell back to .500. The Phils (15-15) have not been two games north of .500 since Oct. 1, 2012.
The Blue Jays, losers of eight of their previous 11 coming into South Philly, took the first of four games the two teams are playing this week in a home-and-home interleague series at Citzens Bank Park and the Rogers Centre. Happ looked at home on visiting turf.
The former Phillies pitcher had his first start of the season almost a year to the day - May 7, 2013 - when he suffered a scary line drive to the forehead that sidelined him for 3 months last season.
"We're boys, we came up together - it was fun to face him," Kendrick said. "With all he's been through, getting hit in the head, his knee, he had back stuff this spring. He looked good. His velocity was good tonight. I'm always pulling for him, except when I pitch against him."
On Twitter: @ryanlawrence21