SAN FRANCISCO -- He has bone-on-bone arthritis in his surgically repaired right knee, no cartilage left and no meniscus. Barry Bonds knows that will never change and his knee won't again be what it once was. But he's trying to get it to the point where it's the best it can be.

That won't happen until the offseason, he said Friday night before he hit his 704th career homer and first in almost a year.

"I could have stayed home until next season," said Bonds, who resumed his chase of Babe Ruth's total of 714 home runs and Hank Aaron's 755 on Monday after missing the season's first 142 games. "I'm still not at 100 percent. Everybody sees me limping out there trying to do my best for the guys to keep us in the race."

But he wasn't in the starting lineup Saturday for the second time this week in a day game after a night game. He hobbled off the field after popping out foul behind the plate in the eighth inning Friday and declared that he might not be able to play again this weekend.

Bonds said he doesn't have the strength in his legs now to swing with the power he's used to, although he hit his first homer in his 11th at-bat and just missed on a few others in the days before connecting off the Dodgers' Brad Penny during the first inning of a 5-4 Giants win Friday.

Bonds said the 20-game, end-of-the-season span to which he has returned is not enough time to make any assessments about how much he really has left in the leg.

"I'll know more about that in the offseason," he said. "I'll know more when I can take some time off and really let it heal. That'll determine whether I'll really be able to get my strength back. There's not enough time now to figure that out. Right now, I'm just trying not to do too much so I can see what I can handle."

Because of the series of injuries and surgeries, Bonds has had to adjust his famous exercise regimen. He hasn't been able to work out his legs with the same consistency that he had during the first 19 years of a stellar Hall of Fame career that includes seven National League MVPs during his time with the Giants and Pittsburgh Pirates.

"Normally, I'd be in the gym right now working out, doing a lot of leg lifts and pushes," Bonds said, sitting in his black leather lounge chair in front of his locker. "But I can't go do what I normally do. I'm sitting in this chair until my back hurts."

Bonds, at 41, has seen the end of his career staring him in the face. He had a taste of it this season, which has been fraught with surgery, rehab, more surgery and rehab again. That right knee has endured four surgeries since 1999 -- three this year during a three-month span.

The first two, on Jan. 31 and March 17, were to repair meniscus. The final one on May 2 was to purge a raging bacterial infection that had gone undetected for perhaps months. One thing is clear: After the January surgery, Bonds banged his knee on a table during a meeting with Giants officials at SBC Park and popped the stitches, which had to be redone.

His recovery was a maze of complications after that. Meanwhile, the Giants paid him $22 million this season to get back to the point where he had played in all five games since his return, starting four and lasting into at least the seventh inning in each of those starts. He is under contract in San Francisco for one more year at $18 million.

The end was cast in the shadow of the recent retirement of NFL receiver Jerry Rice, the former San Francisco 49ers star who was never the same after he tore a knee ligament twice in the late 1990s, only to work his way back both times.

"When you're an athlete, you know that your time is going to come and that time is when you're done," Bonds said. "You know that's going to happen. So you better select a different job if you can't deal with that happening to you. I went through high school. I went through college. I'm going to do the same thing now as I did then -- look forward and say, 'bye.'"

But that's a subject for a later time.

Right now, he's probably best equipped to be a designated hitter, rather than suffer the pounding of playing left field. But that won't happen unless he asks for a trade to an American League team, and Bonds has said he'll finish this contract with the Giants.

He believes he has enough left and he'll always be able to hit a baseball. His first week back has proven nothing to the contrary.

"The thing about leaving the game because of an injury, that's a whole different subject than playing 20 years and then going out," Bonds said. "If I played two years and then I had to go out, that would be painful. That's short-lived. For me, going out right now would be devastating because I know I can still do some things.

"But time is something that you can't prevent. When your time has come, your time has come. You can't hang on."