Despite Roger Clemens' victory last year in his perjury case, a defamation lawsuit filed against the former Yankees ace more than four years ago in federal court in Brooklyn is threatening to keep alive allegations that he used steroids and cheated on his wife.

A magistrate judge in the civil case last week ordered lawyers for Clemens to turn over government documents to the plaintiff, former strength coach Brian McNamee, including 22 FBI reports and notes from an Internal Revenue Service agent that refer to Clemens' alleged affairs. The lawyers had argued the material, some based on FBI interviews of various women, was made up of "inadmissible rumors."

Judge Cheryl Pollak wrote that adultery "is not usually found to be probative of a witness' character for truthfulness or untruthfulness." But, she added, lawyers for McNamee "might be able to cross-examine Mr. Clemens about instances in which he allegedly lied about his relationships, since in that case, the basis for impeachment would be dishonesty."

Given "the sensitive nature" of the FBI reports and IRS notes, Pollak said they would be filed under a protective order that would keep them private for now.

Lawyers representing Clemens in the civil case had sought to withhold more than 1,600 pages of documents from the government's criminal probe on the basis that they were grand jury material. However, the judge found that much of the material — including bank statements, letters and business records — should be turned over to the plaintiffs, saying that "documents produced in response to federal grand jury subpoenas does not automatically shield them from disclosure."

Pollak's order "gives us the essential fruits of the government investigation" in a civil case that doesn't require the higher standard of proof needed in the criminal one, Richard Emery, an attorney for McNamee said Sunday.

"All we have to prove is that Clemens more probably than not lied and that McNamee didn't," he said.

The 2009 federal lawsuit, which seeks unspecified damages, alleges Clemens launched an "intense and coordinated public relations offensive" against McNamee after the trainer told federal investigators and Congress that he injected Clemens more than a dozen times with steroids and human growth hormone from 1998 through 2001.

The suit quotes Clemens saying in a YouTube video in 2007 that McNamee "did not inject steroids into my body either when I played in Toronto for the Blue Jays or the New York Yankees." It also cites an interview with ESPN in May in which Clemens, when asked about McNamee, responded that it was a case of "somebody out there that is really crawling up your back to make a buck."

McNamee called Clemens a "pathological liar" in a story published Sunday in the Daily News.

"Steroid abuse was rampant in Major League Baseball and he was the father of it," McNamee said.

There was no response to messages left Sunday with an attorney for Clemens. Neither he nor McNamee are expected at a status conference set for Wednesday in Brooklyn.

Last year, a Washington jury found the seven-time Cy Young Award winner not guilty of lying to Congress about steroids and human growth hormone. He had adamantly denied using either substance at a 2008 congressional hearing.

The prosecution's case at a two-month trial had relied heavily on the testimony of McNamee, who told jurors he injected Clemens with steroids and HGH many times. The defense focused on how McNamee's story evolved over time, and there was no one else to claim firsthand knowledge of Clemens' drug use.

Former country music star Mindy McCready, who died this year, made headlines in April 2008 when she claimed a longtime relationship with Clemens. He has denied that claim.