SCOTTSDALE, Ariz. — The evidence keeps mounting that Barry Bonds might have been juiced for years.

Steroids. Human growth hormone. Insulin. He may have used them all during his pursuit of the home run record.

An upcoming book written by two San Francisco Chronicle reporters reveals the San Francisco slugger took quite the cocktail of performance-enhancing drugs for at least five seasons beginning in 1998 — despite his constant denials and claims of being clean. Bonds has always insisted he earned all his accolades from hard work.

An excerpt from "Game of Shadows," which details Bonds' extensive doping program, appears in the March 13 issue of Sports Illustrated.

"I won't even look at it. For what? There's no need to," Bonds said Tuesday after a workout at Scottsdale Stadium.

Bonds has long dismissed speculation he used steroids and other substances to turn his average-sized body into a monstrous, home-run hitting machine.

"No, no, no, I don't want to talk about Bonds. I'll see you later," San Francisco manager Felipe Alou said after the Giants' 12-3 win over San Diego in Peoria. He then bolted onto the bus.

Now, even more questions arise about whether Bonds fairly moved up the career homers list to his current spot of No. 3 behind Babe Ruth and Hank Aaron.

Is Bonds' 41-year-old body finally breaking down in part because he's no longer taking the performance-enhancing drugs that aid athletes in their recovery? Is the added weight he's carrying around his middle the result of losing muscle mass he previously had while on steroids — or just a product of undergoing three knee operations last year?

Bonds, who testified before a California federal grand jury investigating steroid use by top athletes, repeatedly has denied using performance-enhancing drugs.

"I've read what was reported," Bonds' agent, Jeff Borris, told The Associated Press. "Barry is looking forward to playing this year and the improved health of his knee, and being as productive as he's ever been."

Baseball did not ban performance-enhancing drugs until after the 2002 season, though there has long been suspicion star players such as Bonds were taking steroids to gain an edge. This book is yet another distraction for Bonds, who has become as accustomed to steroids questions in recent years as he has inquiries related to his powerful left-handed swing.

"It wasn't illegal," Orioles manager Sam Perlozzo said in Florida. "The thing we all worry about is the fact that people discount the fact that you put some numbers up. When you put things like that in jeopardy and in doubt, it's not good for the game. Anytime there's a number out there that we've all thought was natural, it taints the game a little. You wonder about the stats. But we don't know how many did it. Maybe everyone did."

Bonds, a seven-time NL MVP, enters this season with 708 homers, seven shy of passing Ruth and 48 from breaking Aaron's career mark. Bonds said before last season ended that he wanted to get "skinny," but he is about the same size or slightly heavier this spring and has yet to play an exhibition game on his surgically repaired right knee.

Authors Mark Fainaru-Wada and Lance Williams, who led the newspaper's coverage of the BALCO scandal, recount in remarkable detail the specifics of Bonds' drug regimen, which they claim started in 1998 with injections of Winstrol, a powerful steroid also linked to Rafael Palmeiro.

"The Giants have a long-standing policy not to comment on this legal matter," said Staci Slaughter, the team's vice president of communications.

According to the book, Bonds was using two undetectable designer steroids, informally known as the cream and the clear, plus insulin, human growth hormone and other performance enhancers by 2001, when he hit 73 home runs for the Giants to break Mark McGwire's single-season record of 70 set in 1998.

BALCO, the Bay Area Laboratory Co-Operative founded by Victor Conte, kept track of Bonds' alleged drug use in detail, with folders and calendars that chronicled everything from schedules and quantities to his testosterone levels. Much of that information was obtained by federal agents when they raided the lab in September 2003.

According to reports in The Chronicle, Bonds testified to the grand jury in late 2003 that he used a clear substance and a cream given to him by his personal trainer, Greg Anderson, who pleaded guilty in the BALCO case last July to steroid distribution and money laundering. Bonds said he didn't know that what he was using was a steroid, the newspaper reported.

In October, Anderson was sentenced to three months in prison and three months in home confinement. Conte was among three other men who also pleaded guilty to their role in supplying steroids to elite athletes.

"Game of Shadows" is scheduled to be published March 27 by Gotham Books.

The Chronicle reporters, who based the book on a two-year investigation, included an extensive summary on their sources: court documents, affidavits filed by BALCO investigators, documents written by federal agents, grand jury testimony, audio recordings and interviews with more than 200 people.