Feb. 12 (Bloomberg) -- Testimony from Roger Clemens and Brian McNamee will be the focus of tomorrow's congressional committee hearing about performance-enhancing drugs in Major League Baseball after three other witnesses were dropped.

Andy Pettitte, Chuck Knoblauch and Kirk Radomski won't testify tomorrow, House Oversight and Reform Committee chairman Henry Waxman said in a statement. Pettitte yesterday asked the committee to be excused from publicly testifying against Clemens, his friend and former teammate, the New York Times reported.

Knoblauch is a former New York Yankees teammate of Clemens and Pettitte, and Radomski is a former New York Mets clubhouse worker who pleaded guilty to distributing steroids to baseball players. Pettitte, Knoblauch and Radomski all gave closed-door depositions to the committee ahead of tomorrow's hearing on Capitol Hill, as did Clemens and McNamee.

``Mr. Knoblauch and Mr. Pettitte answered all the committee's questions and their testimony at the hearing is not needed,'' Waxman said in the statement.

McNamee has said he gave performance-enhancing drugs to both Clemens and Pettitte, who has admitted to using human growth hormone five years ago while recovering from an injury. Clemens, a seven-time Cy Young Award-winning pitcher, has repeatedly denied taking steroids or HGH.

Pettitte Affidavit

Pettitte's affidavit mostly matched McNamee's, Representative Tom Davis, the committee's ranking Republican member, told Newsday. Clemens said in his affidavit that Pettitte and McNamee were mistaken.

Either Clemens or McNamee may face perjury charges if the committee determines one of them has lied about Clemens's involvement in performance-enhancing drug use.

Pettitte asked out of tomorrow's hearing because he didn't want to say something during the nationally televised session that might hurt Clemens, the Times said, citing a member of the congressional staff it didn't identify.

McNamee was questioned by the committee for seven hours on Feb. 7 and his lawyers presented photographs of vials and syringes that they say support McNamee's claims that he injected Clemens with steroids and human growth hormone.

In former Senator George Mitchell's report on steroids in baseball, McNamee said he injected Clemens with steroids and HGH between 1998 and 2001. Charlie Scheeler, one of Mitchell's investigators, will join McNamee and Clemens in testifying before the congressional committee tomorrow.

Vitamin, Painkiller

Clemens, 45, gave his five-hour sworn testimony to House lawyers on Feb. 5, denying he used performance-enhancing drugs. He's said that McNamee only injected him with the vitamin B-12 and the painkiller Lidocaine.

Clemens's lawyer Rusty Hardin last week compared his client's case to the prosecution of three Duke University lacrosse players who were accused of raping a woman, only to be found innocent later.

``I warn you, in five, six or seven months, any of you who got on the bandwagon about Roger taking steroids is going to be embarrassed,'' Hardin told reporters Feb. 7.

Internal Revenue Service special agent Jeff Novitzky, the lead investigator in the U.S. government's probe of steroids in professional sports, might attend tomorrow's hearing. Novitzky headed federal perjury investigations of baseball All-Star Barry Bonds and track champion Marion Jones during his 5 1/2-year review of steroids in sports.

Bonds, Major League Baseball's all-time home-run leader, pleaded not guilty to perjury and obstruction of justice in December after the government accused him of lying to grand jurors about using steroids. Jones, who won a record five medals at the 2000 Olympics in Sydney, last month was sentenced to six months in prison for lying in two federal grand jury investigations about steroid use.

To contact the reporter on this story: Erik Matuszewski in New York at matuszewski@bloomberg.net

Last Updated: February 12, 2008 10:21 EST