He was leaving, but not to join the Blue Jays. He was headed with his Phillies teammates to San Francisco, where they open a four-game series against the Giants on Thursday.
Happ, who allowed three hits and two runs in six innings in a 4-0 loss to the Diamondbacks, had been the subject of trade rumors as the Phillies pursued Blue Jays ace Roy Halladay. The Blue Jays wanted Happ, Double-A Reading right-hander Kyle Drabek and Class A Clearwater outfielder Dominic Brown.
The Phillies balked at the price and instead acquired left-hander Cliff Lee and outfielder Ben Francisco from the Indians for four other prospects on Wednesday.
Happ is safe.
"Experienced gained," he said.
Happ, who is 7-2 with a 2.97 ERA, made one mistake Wednesday: a 2-1 changeup that Justin Upton hit for a two-run home run in the first inning. He retired 17 of the final 20 batters he faced in his six-inning stint. It wasn't enough as the Phillies managed just four hits in six-plus innings against Yusmeiro Petit, who entered the game 0-5 with a 7.68 ERA.
Hitters were frustrated afterward.
"He made good pitches," Greg Dobbs said. "He hit the corners. He changed speeds. He's deceptive. He kept us off balance."
But Happ's performance -- other than the homer to Upton -- illustrated why he is a National League Rookie of the Year candidate and why the Blue Jays wanted him so badly.
"It looks to me like he handled it pretty good," Phillies manager Charlie Manuel said of the trade talks. "Usually when you're a pro, you handle it. That's how you act. He can handle it. He's a big leaguer."
Happ received numerous messages Wednesday morning when word spread that the Phillies had acquired Lee for Jason Knapp, Carlos Carrasco, Jason Donald and Lou Marson. Happ also spoke with his agent.
"You can waste a lot of energy thinking about it, so I tried not to," Happ said of the endless rumors. "I don't know if I didn't really believe it or if it was kind of surreal. It really wasn't too difficult for me, I guess. I'm glad to be here."
His teammates echoed that sentiment.
"They were able to pull that off and not give away Happ," closer Brad Lidge said. "Wow. Getting a guy like Cliff Lee and getting a great outfielder, too, is pretty amazing considering we didn't have to give away anybody on our team to do it."
Teammates patted Happ on the back as he arrived in the clubhouse Wednesday afternoon.
He smiled. He looked relieved.
"The guys have been great," Happ said. "They've been ribbing a bit, but they were really good today. And that means a lot to hear stuff like that from your teammates. I'm glad that they're glad that I'm here, and I'm even more glad that I'm still here."
Happ has had an interesting year so far. He opened Spring Training in a four-man competition for the fifth spot in the Phillies rotation with Chan Ho Park, Kyle Kendrick and Carrasco. He pitched well, but Park pitched a bit better and got the job.
Happ started the season in the bullpen. He went 2-0 with a 2.49 ERA in 12 appearances, but ultimately replaced Park in the rotation.
But will he stay there?
There is another numbers game going on. The Phillies have seven starters with the team or on the way: Happ, Lee, Cole Hamels, Joe Blanton, Jamie Moyer, Pedro Martinez and Rodrigo Lopez. Martinez is expected to replace Lopez. But who else gets bumped?
Phillies general manager Ruben Amaro Jr. said the Phillies signed Martinez to be a starter. Pitching coach Rich Dubee agreed. Dubee also said Moyer is not a legitimate bullpen candidate.
"Things happen for a reason," Happ said. "I've been hearing that from a lot of people since stuff has been going down. I'm here and I'm trying to do what I can do. Hopefully that means something. It's all right to go through stuff like that. It's a character builder. I'm not the only one that this has ever happened to. This stuff happens all the time."
But for now it is over. And Happ is thankful for that.
Todd Zolecki is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.