PHOENIX(AP) Philadelphia rookie J.A. Happ may have lost his spot in the starting rotation when the Phillies traded for ace lefty Cliff Lee .

Happ still smiled, though, after a 4-0 loss to the Arizona Diamondbacks on Wednesday night, because he was heading to San Francisco with the NL East-leading Phillies after the game.

Happ (7-2) had been rumored to be trade bait in recent weeks.

''I'm glad I'm here, that's for sure,'' Happ said.

With the acquisition of Lee from the Cleveland Indians , Phillies manager Charlie Manuel said he would ponder changes to his rotation. Happ made his case to stay, allowing two runs and three hits in six innings. He walked two and struck out five.

''Things happen for a reason,'' Happ said. ''I've been hearing that from a lot of people when all this stuff's been going down. You know, I'm here and trying to do what I can do, so hopefully that means something.''

Justin Upton homered and drove in three runs and Chris Snyder added a solo shot for Arizona, which salvaged the finale of a three-game series.

The deal for Lee, the reigning AL Cy Young Award winner, sent a jolt through the Phillies clubhouse when it was announced during batting practice. But it didn't help the Phils against journeyman Yusmeiro Petit (1-5), who matched a career high with eight strikeouts and won for the first time since Aug. 23, 2008, a span of 11 starts.

''Bottom line was, we just didn't hit him,'' Manuel said.

The Phillies lost for only the sixth time in 25 games this month and saw their NL East lead drop to six games over Florida.

The Phillies beat All-Star Dan Haren on Tuesday night, but they seemed baffled by Petit, who appeared on his way of the rotation - and possibly the big leagues - as recently as a week ago.

In three of Petit's July starts, the Diamondbacks' opponents had put up football-like scores of seven, 14 and 10 runs. He entered with a 7.68 ERA.

Facing the potent Phillies lineup, Petit gave up a leadoff single to Jimmy Rollins , then began to cruise. He allowed a single to Raul Ibanez leading off the second before retiring 15 of the next 16 batters, including 13 straight at one point.

''It feels good, especially against that team,'' Petit said through an interpreter. ''It's a strong and pretty good-hitting club. It makes you feel good about yourself.''

After Ryan Howard singled and Ibanez doubled to open the seventh, Petit left to a standing ovation from the Chase Field crowd.

Juan Gutierrez came on and struck out Jayson Werth and Greg Dobbs before walking Carlos Ruiz to load the bases. Gutierrez escaped the jam by retiring pinch-hitter Pedro Feliz on a fly to center.

''To come out of that unscathed is pretty much the story of the game in that one inning,'' Arizona manager A.J. Hinch said.

Petit allowed four hits in six innings, walking one and striking out eight.

''That was as effective and efficient as I've ever seen him,'' Hinch said. ''He had a really good changeup. He mixed up his location. To get the swing-and-misses out of that order showed how much command and stuff that he had tonight.''

Happ was nearly as effective as Petit.

In the first, Happ gave up a leadoff single to Stephen Drew and a homer to Upton, who hit a changeup into the left field seats. Happ rolled through the next five innings, retiring 15 of the next 17 hitters.

Snyder homered to lead off the seventh against Scott Eyre - the catcher's first since May 25. Upton knocked in the final run with a single in the eighth.

NOTES: Philadelphia CF Shane Victorino left in the seventh with a left knee contusion. Victorino got up slowly after diving to snag Ryan Roberts ' sinking liner in the first inning. Victorino went 0 for 3. ... Arizona 3B Mark Reynolds ' streak of three games with a home run ended one shy of tying the club record. He also had a 12-game hit streak snapped. ... In the eighth, the umpires reviewed a drive by Arizona's Gerardo Parra off the top of the right field fence, confirming their ruling of a double.