US baseball home run king Barry Bonds tested positive for steroids in November 2000, months before his record 73rd home run season, US prosecutors said on Thursday.
The allegation came in a legal filing in his steroid perjury case which referred to Bonds' long-time trainer, Greg Anderson.
"At trial, the government's evidence will show that Bonds received steroids from Anderson in the period before the November 2000 positive drug test, and that evidence raises the inference that Anderson gave Bonds the steroids that caused him to test positive in November 2000," US Attorney Joseph Russoniello wrote.
Russoniello, acting for the US government, made the assertion in a document that asked a federal court to reject Bonds' motion last month to dismiss the charges that he lied about past steroid use.
Dennis Riordan, one of Bonds' lawyers, said the slugger's defence team would respond to the filing by next Thursday and would not have immediate comment on Thursday.
In December, the record seven-time National League Most Valuable Player pleaded not guilty to lying to a federal grand jury in 2003 when he denied using performance-enhancing drugs.
He testified in the BALCO sports steroid case, which ended up jailing his personal trainer, Anderson, and the head of the BALCO lab near San Francisco.
The latest government motion also referred to a question by a prosecutor during the BALCO case to "determine why Bonds apparently tested positive for anabolic steroids in November 2000."
To date, prosecutors have revealed little about the evidence they have in the case against Bonds, the greatest hitter of his era long dogged by suspicions about doping.
The motion to dismiss the case has prompted prosecutors to reveal a bit more of their hand.
They referred to a calendar "that showed that 'BB' received steroids in December 2001." The filing further alleged that Bonds discussed or took human growth hormone.
Referring to a question as to whether Anderson talked to Bonds about or gave him human growth hormone, Bonds said no. "The government will show at trial only that Bonds' answer to that portion of the question is knowingly false," the motion said.
The latest details to emerge in the ever-widening baseball doping scandal came just a day after Roger Clemens, one of the greatest pitchers in Major League Baseball history, clashed under oath with his former trainer at a congressional hearing over the trainer's claims he injected Clemens with illegal performance-enhancing drugs.
A US federal judge in San Francisco is expected to hold a hearing on Bonds' motion to dismiss the case on February 29.
