SAN FRANCISCO " Barry Bonds' personal trainer was ordered Monday to appear before a federal judge and say whether he'll break his silence and testify at the slugger's perjury trial.
U.S. District Judge Susan Illston summoned Greg Anderson for the unusual hearing, scheduled for Wednesday.
Anderson is considered a vital witness for the government as it tries to prove Bonds lied to a grand jury investigating steroid use by athletes. Prosecutors said the trainer can directly link Bonds to three positive drug tests and other evidence collected during a September 2003 raid at the Bay Area Laboratory Co-Operative, which was at the center of the steroids probe.
The judge has barred prosecutors from showing the jury the test results because Anderson is refusing to testify. Anderson is alleged to have collected the urine samples for drug testing at the lab. Without his testimony confirming the collection, Illston has said there is no way to prove the samples belong to Bonds.
Similarly, the judge said calendars that prosecutors say chart Bonds' use of performance-enhancing drugs can't be introduced without Anderson's testimony that he created them.
Messages left Monday with Anderson's attorney, Mark Geragos, were not immediately returned.
The trainer has already spent a year in prison on a contempt of court charge for refusing to testify about Bonds to a 2006 grand jury. He also declined to discuss his relationship with Bonds when asked by federal agents during a September 2003 raid of his home.
Bonds is charged with 10 counts of making false declarations to a grand jury and one count of obstruction of justice.
Illston scheduled the Wednesday hearing after Bonds' attorneys objected to having Anderson's refusal to testify " and possible jailing " play out in front of the jury. Defense lawyers argued that would be unfair to Bonds, who owns the major league record for home runs with 762.
Illston's decision to hold a separate hearing with Anderson before trial, scheduled to begin next Monday, will keep that drama away from jurors.
Prosecutors and Bonds' lead attorney, Allen Ruby, declined comment Monday.
Legal experts expect the judge to put Anderson on notice that he will be put behind bars for the duration of the anticipated monthlong trial if he refuses to participate. Then, they say, Anderson would be called to the witness stand during trial " but outside the presence of jurors " and asked his intentions again. If he refuses to testify at the point, he may be jailed.
Federal prosecutors are discussing whether to appeal the judge's decision to bar the three steroids tests from being introduced at trial. They have until the first juror is seated " probably on March 3 " which would then delay the trial for an undetermined time. The 9th U.S. Circuit Court of Appeals would decide the issue.
"It's very hard to overturn evidentiary rulings," said Howard Wasserman, who teaches evidence at Florida International University College of Law and writes about sports law. "Plus it was a very good, solid ruling."