SAN FRANCISCO – Home-run king Barry Bonds pleaded not guilty on Thursday to charges he lied to a grand jury about taking steroids, and a federal judge said some drug tests and other government evidence looked too weak for trial.

The judge said, however, a transcript of an expletive-laden, locker room conversation between two of Bonds's associates discussing the slugger and doping seemed acceptable as evidence.

Bonds, 44, stood quietly in a tan suit as his lawyer pleaded not guilty on his behalf to 10 counts of lying to the jury and one count of obstruction of justice.

It was Bonds' third time responding he was innocent after prosecutors were twice required to revise the charges against him.

An elderly woman wrung a smile out of Bonds as he walked into the courtroom, and he gave her a hug and whispered to her as he left. "I told him I loved him," the woman said afterward, declining to give her name.

Bonds passed Hank Aaron to become Major League Baseball's career home run leader in 2007, but the San Francisco Giants declined to give him a new contract after the season. A federal grand jury that year charged Bonds with lying when he testified in the BALCO lab steroid case that he had never used steroids.

At a second hearing on Thursday, U.S. District Judge Susan Illston said she did not think prosecutors had proved steroid-laced urine from 2000 and 2001 tests at BALCO labs belonged to Bonds.

Handwritten notes by Bonds' former trainer Greg Anderson and calendars purporting to show Bonds' use of performance enhancement drugs also relied on hearsay to prove the link, Illston said, siding with the defense in what she called her preliminary thoughts.

Illston has not yet made a final ruling on the evidence and gave prosecutors the chance to reargue some points before the trial, which is scheduled to start on March 2 and last about a month.

The trial may be full of unusual evidence. Lawyers briefly discussed whether testimony about the size of Bonds's testicles -- and whether they were shrunk by use of steroids -- was reasonable, and will submit further arguments on the matter.

'Pit of mendacity'

The government wants to show jurors other drug tests, and a transcript of a talk between Anderson and Steve Hoskins, an old friend and business associate of Bonds, may be allowed.

Defense lawyers said the 2003 conversation recorded in the Giants' locker room was vague and untrustworthy.

"We are talking about a men's locker room. There is no greater pit of mendacity in the world," attorney Dennis Riordan said. But the judge indicated she probably would allow it.

The case started with the BALCO lab scandal, which implicated Bonds and other elite athletes. BALCO's owner, Victor Conte, and Anderson were imprisoned in connection to steroids distribution. Drug scandals also resulted in imprisonment and disgrace for ex-track-and-field stars Marion Jones and Tim Montgomery.