SAN FRANCISCO — Barry Bonds' personal trainer still isn't talking.

Greg Anderson, who spent more than a year in prison for refusing to testify against the slugger, declined comment today after a judge rejected government demands that he and three others convicted of distributing steroids return evidence related to the notorious Bay Area Laboratory Co-Operative drug ring.

Staying quiet is a position Anderson has taken with the media and federal prosecutors alike since he was first ordered to testify in 2006 before a grand jury investigating Bonds for perjury. A federal judge sent Anderson to prison for snubbing the grand jury and he remained jailed until Bonds was indicted Nov. 15 for allegedly lying under oath about his steroid use.

Bonds has pleaded not guilty and a judge will consider his request to toss out his case at a hearing Feb. 29.

The U.S. attorney's office refiled court papers Friday opposing Bonds' dismissal request. Prosecutors refiled because the original documents filed Thursday contained two crucial typographical errors that mistakenly stated Bonds flunked a steroids test in November 2001.

The indictment of Bonds, unsealed last year, included references to a drug test Bonds failed in November 2000, and a spokesman for the U.S. attorney's office said prosecutors simply got the date wrong in Thursday's filing. Still, the mistake prompted at least one erroneous report that was quickly picked up by TV, radio and online news reports.

Allen Ruby, a lawyer for Bonds, declined to comment on the error.

Anderson's attorneys said the trainer will refuse to testify at a Bonds trial, a stance that will likely land him in prison again if the home run king ends up in front of a jury.

At issue Friday was the government's attempt to retrieve the sensitive legal documents prosecutors turned over to Anderson, BALCO founder Victor Conte, former BALCO executive James Valente and former track coach Remi Korchemny so they could defend themselves against drug charges.

All four pleaded guilty to drug charges and Anderson and Conte each served several months in prison.

On Friday, U.S. District Judge Susan Illston refused to order the four to return the documents to federal prosecutors.

Assistant U.S. Attorney Jeff Nedrow said the government feared that the identities of many high-profile athletes who testified behind closed doors as part of the BALCO investigation would be leaked to the media if the documents weren't returned or destroyed.

Nedrow said the convicted steroid dealers each had 30 to 40 transcripts of athletes' testimony before the grand jury, as well as confidential search warrant information.

"A number of athletes who testified have never been made public," Nedrow said.

Conte's lawyer Ed Swanson, who argued on behalf of the four BALCO figures, said they needed to retain the documents in case any of them were called as witnesses in future steroids prosecutions. Aside from Bonds, cyclists Tammy Thomas and track coach Trevor Graham have pending perjury cases that may require some of the BALCO figures to testify.

Illston said the files were to remain at the offices of the BALCO figures' attorneys, although Anderson lawyer Mark Geragos said he doesn't have any of the documents because the trainer's previous attorney lost them.