SAN FRANCISCO -- Federal prosecutors on Thursday cut the number of felony charges Barry Bonds faces from 11 to five.

Major League Baseball's home run leader still faces the same punishment he always has, but the paring of the charges still underscored the troubles prosecutors have encountered since indicting him for the first time in 2007 for allegedly lying to a grand jury about his steroid use. Bonds has pleaded not guilty.

The indictment unsealed Thursday was the fourth version of the charges against Bonds. The document reflects the hit the government's case took when the slugger's personal trainer made clear his willingness to go to jail on contempt of court charges instead of testifying against his former client.

The trainer, Greg Anderson, has already served more than a year in prison for refusing to testify before the grand jury investigating Bonds. Anderson, who prosecutors allege supplied Bonds with steroids, is scheduled to appear in court before Bonds' March 21 trial to formally tell the judge of his plans for the trial. Anderson's attorney, Mark Geragos, said Anderson will reiterate his refusal to take the witness stand. It's likely that Anderson will be jailed for the duration of the trial, which is expected to last up to a month.

Prosecutors on Thursday removed from the indictment perjury charges that relied on dates found on so-called doping calendars found in Anderson's apartment that prosecutors allege show Bonds' drug regimen. U.S. District Judge Susan Illston ruled those documents inadmissible at trial because of Anderson's refusal to authenticate them on the witness stand.

In the new indictment, they reduced from nine to three the number of charges alleging Bonds lied under oath when he testified that he never knowingly took performance-enhancing drugs.

He is still charged with making false statements for telling the grand jury that no one other than his doctor ever stuck a needle in his body and a catch-all charge that he obstructed the grand jury's investigation into sports doping with his allegedly misleading testimony.

Each count carries a potential sentence of 10 years in prison. However, federal sentencing guidelines for a first offense on these charges generally call for a total sentence of 15 to 21 months.

A hearing is scheduled for Friday on whether the jury should hear a secret tape recording made between Bonds' former business partner Steve Hoskins and Anderson allegedly discussing Bonds' steroid use. The judge has excused Bonds from attending the hearing.

A ruling for Bonds would be another blow to the prosecution.

In March 2003, Hoskins and Anderson stood in front of Bonds' locker in the San Francisco Giants clubhouse and appeared to discuss steroids and needles.

Hoskins secretly recorded the conversation with Anderson and later turned it over to federal investigators. Prosecutors want the jury to hear the tape to bolster their case against Bonds.

Prosecutors allege that Anderson can be heard in the recording boasting about supplying Bonds with a new steroid designed to evade urine tests. The prosecutors plan to show the jury the results of a urine test collected from Bonds in 2003 as part of Major League Baseball's inaugural testing program that included all players.

Bonds' test initially came back negative. But prosecutors went back and tested it after famed anti-doping chemist Don Catlin developed a test for the designer steroid THG, which allegedly showed up in Bonds' urine. They say the Hoskins recording shows Anderson discussing Bonds using THG.

"But the whole thing is everything I've been doing at this point, it's all undetectable," Anderson is recorded as telling Hoskins as the Giants' Benito Santiago walks by and the two lower their voices, according to prosecutors. "See, the stuff that I have, we created it. And you can't buy it anywhere. You can't get it anywhere else. But you can take it the day of and pee. And it comes up with nothing."

That Anderson spoke in low tones in a private setting hardly establishes a knowledge of illegality, particularly since, as the recording makes clear, the conversation as a whole turned at many points to "patently innocuous events," Bonds' attorney wrote in a Feb. 4 court filing. "The statements themselves, moreover, are difficult to discern. And they are far more ambiguous than those considered trustworthy in the cases cited by the government."

Hoskins told federal investigators that he made the recording to convince Bonds' father, former major league player Bobby Bonds, that his son was using PEDs.

According to prosecutors, Bonds' father "did not that believe that his son was using steroids," so Hoskins decided to offer him recorded proof. Hoskins turned over the recording to prosecutors after they began investigating Bonds for allegedly lying to the grand jury in December 2003.

Information from The Associated Press was used in this report.