A federal judge ordered Barry Bonds' personal trainer to testify Thursday before a grand jury investigating whether the baseball star lied about using steroids.

Greg Anderson has been ordered to appear before the grand jury at 2:30 PDT this afternoon — when he'll have another tough decision to make.

If Anderson refuses to testify, he will be sent back to prison for contempt of court.

Anderson, 40, has served time twice in less than a year in connection with a Bay Area-based performance-enhancing drug ring linked to some of the top athletes in the world, including Bonds, Yankees slugger Jason Giambi and sprinter Tim Montgomery.

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The trainer was released from prison last month after serving 15 days for refusing to testify, but only after that grand jury's term expired.

He also served three months in prison and three months of home detention after pleading guilty to steroid distribution and money laundering stemming from the government's investigation of the Bay Area Laboratory Co-Operative, which allegedly supplied Bonds and other athletes with performance-enhancing drugs.

Government lawyers are investigating whether San Francisco Giants slugger Barry Bonds lied under oath when he told an earlier grand jury he didn't know whether the substances given to him by Anderson were steroids.

The grand jury probe also reportedly is focused on whether the San Francisco Giants slugger paid taxes on the sale of hundreds of thousands of dollars worth of sports memorabilia.

Anderson has vowed to remain quiet.

If he continues to do so he could be held until he either agrees to testify, or the grand jury's term expires in 17 months or Judge William Alsup becomes convinced that the divorced father will never break his vow of silence.

Anderson has refused four times to testify before federal grand juries investigating Bonds.

Government lawyers are investigating whl a grand jury who gave them the information. The reporters have said they would go to jail rather than reveal their source or sources.

Anderson's lawyers also say the agreement he made with prosecutors to plead guilty last year in the BALCO case stipulated he wouldn't have to cooperate with investigators. They contend Anderson also shouldn't have to testify because he was the target of an illegal wiretap.

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