As head trainer Stan Conte watches, Barry Bonds limps back into the dugout. (Rusty Kennedy/AP)

After missing 10 games with a strained right hamstring, Bonds had three hits including his 29th home run but aggravated the injury on an eighth-inning shoestring catch during the Giants' 8-6 loss at Veterans Stadium, casting doubt on when he might return again.

Bonds, who told reporters Tuesday that there was a chance he'd play in Thursday's series finale, revealed after the game that he knew all along he'd be playing Wednesday.

"So much for the ESPN reports," said Phillies manager Larry Bowa. "I figured when he took batting practice that there was a good chance."

With Bonds in the starting lineup, as well as All-Star catcher Benito Santiago, the Giants offense resembled its usual power supply. In the first inning, Jeff Kent hit a two-run homer and Bonds followed with a double down the right-field line, jogging easily into second base.

After a fourth-inning strikeout, Bonds hit a solo homer off Mike Timlin in the fifth inning, his 596th career blast and first ever off the right-hander, making him the 357th pitcher to give up a home run to baseball's fourth-most prolific slugger.

"There's a few names in his book," said Timlin, who earned the victory in his Phillies debut. "I was hoping to keep my name out of it, but that's all right."

Bonds said he was not surprised that he swung the bat well in his return and neither were his teammates.

"It's a joke," said Rich Aurilia, who flied out with the bases loaded in the ninth inning to end the game against Jose Mesa. "Every time he misses time and comes back, he does well. He's just a great player. It doesn't matter how long he's been out or what he's out for, he comes back and does his job and helps the team."

But Wednesday night was no joking matter for the Giants.

Barry Bonds   /   LF
	Height: 6'2" Weight: 210 Bats/Throws: L/L More info: Player page Stats Splits Hit chart Giants site

That play was the epitome of the Giants' dilemma. With Philadelphia leading by two runs in the eighth inning, Marlon Anderson hit a sinking line drive to left field that Bonds snared, but he immediately limped as he came to a stop. The team had hoped he could keep the injury at the forefront of his mind while he played, but that's a difficult task for a competitor such as Bonds.

"It's not easy," he said. "The instincts of the game kick in. There are a lot of variables out there."

The pain on his face as he hobbled back to his position was as obvious as the frustration on manager Dusty Baker's following the loss.

"We were hoping to get through the night without a tough play in the outfield," he said, adding that Bonds was not scheduled to play Thursday even before the setback. "That's when you usually reinjure something, so I hope it's okay. Dang, boy that was a tough one right there."

Bonds said the pain was not as sharp as the kind he felt in Los Angeles on July 19, when the rubber warning track played a role in the original injury. But he does not think the artificial turf at Veterans Stadium -- which Aurilia lambasted after the game -- had much to do with the latest recurrence.

"It would have happened either way," said Bonds.

The left fielder will not play Thursday and his status for the three-game weekend series in Pittsburgh is also up in the air.

"It's hard to tell," said Conte, who does not plan to take an MRI. "We'll look at a risk and reward situation again with him, Dusty, [general manager] Brian [Sabean], and we'll talk to our doctors tomorrow."

Even with the injury, Bonds remained in the game and came to the plate against Mesa representing the go-ahead run with two out in the top of the ninth inning. Bowa headed to the mound and told his closer to walk Bonds on four pitches, putting him within three intentional walks of tying the single-season record of 45 set by Willie McCovey in 1969. As Bowa walked back to his dugout, he expressed his thoughts to Bonds.

"I just told him he's not going to beat us," said Bowa. "I didn't say it like that. He's a good guy in the dugout. When he's in the batter's box, he's not a good guy."

Mesa followed orders and then got Aurilia to fly out to end the game. For Mesa, it was his 29th save of the season, making a winner out of Timlin (2-3) and a loser out of Giants left-hander Troy Brohawn (0-1). "We had the right guys up in the ninth and Mesa made some good pitches," said Baker. "Boy, I thought we were going to get that game. I thought we were on the road to victory."

The loss dropped San Francisco one game behind the Dodgers for the Wild Card spot and six games back of Arizona in the NL West, equaling the Giants' largest deficit of the season.

Josh Rawitch covers the Giants for MLB.com and can be reached at jrawitch@sfgiants.com. This story was not subject to the approval of Major League Baseball or its clubs.