SAN FRANCISCO - The news of Roy Halladay's shoulder surgery has a trickle-down effect on the entire 25-man roster, and Jonathan Pettibone is one of those who could be most affected.

The 22-year-old pitcher was competent again during a 4-3 loss Wednesday in his quest to secure a permanent rotation spot. Pettibone was not hit hard. He threw 112 pitches in 52/3 innings, and it was the last one that bothered him most. Barry Zito, the opposing pitcher with a lifetime batting average of .103, shot a single past a diving Kevin Frandsen at first base for an insurance run in the sixth.

"That'll haunt me for some time," Pettibone said. "I looked on the replay, and it wasn't a terrible pitch, but we were pitching him like that the whole game, so he was just ready for it."

The righthander, who got a no-decision, is 2-0 with 3.63 ERA after four starts.

"To be his first time up in the major leagues, he's held his own," manager Charlie Manuel said. "He's done pretty good."

The leash was longer Wednesday than ever before in Pettibone's brief major-league career. With both Halladay and John Lannan sidelined, he is now a fixture in the rotation.

"Each time out, you get more and more comfortable," Pettibone said. "Your confidence gets up each time out. You just kind of build off that. From there, I don't really know what's going to happen. All you can do is focus start to start and go from there."

Extra bases

It was a sweet moment for Kevin Frandsen when he homered in the fourth inning. Frandsen, a Bay Area native and former Giant, spent the three days savoring his return. After the game, Giants president Larry Baer visited the Phillies clubhouse to congratulate Frandsen. . . . The Phillies' last 13 home runs are solo shots. . . . Jimmy Rollins' 11 doubles are tied for most in the National League.