Legendary pitcher Roger Clemens asks his ex-trainer why he lied about injecting him with performance-enhancing drugs and urges Brian McNamee to come forward with the real story in a tape-recorded conversation between the two men played for reporters on Monday.

"You just need to come out and tell the truth," Clemens tells McNamee. "I don't know why you did it. ... So much of it is untrue. It's tearing everybody apart. ... I'm numb, my family's numb. So many of the people we worked with are going crazy. They just can't believe what's being said."

The taped call was played at a Monday afternoon press conference in Houston, held by Clemens and his attorney Rusty Hardin only hours after Clemens filed a defamation lawsuit against McNamee.

"I did what I thought was right," McNamee insists to Clemens. "Tell me what you want me to do. I'll fly out there tomorrow. You treated me better than anybody. I learned from you how to raise my kids."

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Much of the call between the two men is calm and civil, with McNamee sounding contrite and remorseful but later growing increasingly upset.

"Everybody has ulcers over this, man," Clemens says at one point. "For the life of me, I don't understand why you would tell guys I used steroids." He laments about how the scandal has destroyed his family.

"I understand, I understand," McNamee replies.

"I'm telling the truth. I want it out there," Clemens says. "I just need somebody to tell the truth."

"Tell me what the f— you want me to do," McNamee says, his voice rising. "I'll go to jail; I'll do whatever you want."

"I'm devastated over this," Clemens responds. "I'm hurt, I'm upset ... I just know that I didn't do it."

After the recording was played, an emotional Clemens told reporters that he has been injected with vitamins like B-12 "forever" by his trainers and didn't realize that McNamee has no medical license.

"I was under the impression that he did," Clemens said. "I've gotten shots from Brian McNamee of B-12 and Litacain. I don't know where he got it."

The pitcher, who appeared angry and close to tears at times during Monday's Q and A session, said that he'd be afraid of what would happen to McNamee if he were to show up at the press conference.

"My family is very upset. I'm trying to keep my composure during all of this," said Clemens.

He declined to criticize fellow baseball player Andy Pettitte, who was also named as having used steroids after a federal investigation.

"Andy is my friend," Clemens said.

Clemens filed his lawsuit Sunday night in Harris County District Court in Texas, listing 15 alleged statements McNamee made to the baseball drug investigator George Mitchell. Clemens claimed the statements were "untrue and defamatory."

"According to McNamee, he originally made his allegations to federal authorities after being threatened with criminal prosecution if he didn't implicate Clemens," according to the 14-page petition, obtained early Monday by The Associated Press

The suit, first reported by the Houston Chronicle, states that when McNamee told others that when he first was interviewed by federal law enforcement last June, he denied Clemens had used steroids or human growth hormone. The suit quotes McNamee as saying he was pressured by Assistant U.S. Attorney Matthew Parrella and IRS Special Agent Jeff Novitzky — key members of the BALCO prosecution — to implicate Clemens. The suit did not attribute where the quote from McNamee was obtained.

"After this exchange, and for the first time in his life, McNamee stated that he had injected Clemens with steroids in 1998, 2000 and 2001," the suit said. "Following his recantation, McNamee has relayed that he magically went from a `target' in a federal criminal drug investigation to a mere `witness,' so long as he continued to `toe the line."'

The suit says that when McNamee initially refused a request from federal authorities that he speak to Mitchell, he was threatened with prosecution. Clemens said McNamee decided only then to cooperate with Mitchell and the suit said McNamee told others that the interview "was conducted like a Cold War-era interrogation in which a federal agent merely read to the Mitchell investigators McNamee's previously obtained statement and then asked McNamee to confirm what he previously stated."

Clemens asked that damages be determined by a jury.

"Clemens' good reputation has been severely injured," the suit said. "McNamee's false allegations have also caused Clemens to suffer mental anguish, shame, public humiliation and embarrassment."

McNamee's lawyers are likely to remove the case to U.S. District Court in Houston, since Clemens and McNamee reside in different states. McNamee also could ask that the suit be moved to federal court in New York.

"His position has never varied," said Clemens' attorney Rusty Hardin in a press conference Monday, adding that before he was hired to represent the legendary pitcher, "I didn't know him from Adam. I had no idea whether he was a truth teller, whether he had done it or not."

Hardin said he had no reason to believe that the government had handled its investigation improperly. Hardin opened a late afternoon news conference Monday in Houston that Clemens was also attending.

Clemens, a seven-time Cy Young Award winner, sounded indignant and defiant in a segment of CBS's "60 Minutes" broadcast Sunday night, his first interview since McNamee accused him. The two are approaching a potential confrontation if they testify under oath at a Jan. 16 hearing on Capitol Hill.

The most prominent player implicated in last month's Mitchell Report, Clemens steadfastly maintained his innocence and called McNamee's allegations "totally false."

"If he's doing that to me, I should have a third ear coming out of my forehead. I should be pulling tractors with my teeth," said Clemens, who wore a lavender button-down shirt during the interview, taped Dec. 28 at his home in Katy, Texas.

On Friday, when the House Committee on Oversight and Government Reform invited Clemens and McNamee to testify, the pair spoke by telephone, an individual close to the situation said, speaking on condition of anonymity because public comments weren't authorized. The conversation first was reported Sunday by Newsday.

The individual would not say what was discussed.

Clemens' lawyer, Rusty Hardin, told the Chronicle that it was McNamee who arranged to talk to Clemens on Friday but instead of getting back to Clemens the conversation was leaked "with spin" to Newsday.

"We kept thinking McNamee might change his mind and come to his senses and admit he was lying," Hardin told the Chronicle.

McNamee also had been contemplating a suit.

"We welcome a lawsuit. It makes our decision easy," Richard Emery, one of McNamee's lawyers, said earlier Sunday. "If he sued McNamee, it would make things very simple."

During the "60 Minutes" segment, Clemens said he might be willing to take a lie-detector test and was "shocked" close friend Andy Pettitte used HGH. He said — again — that he probably will retire.

A fiery look in his eyes and stubble on his face, Clemens told CBS's Mike Wallace that he would have spoken with Mitchell had he been aware of McNamee's accusations.

"I thought it was an impassioned, disingenuous and desperate plea," said Earl Ward, McNamee's primary lawyer.

One of the few revelations in the much-hyped interview came when Clemens was asked whether he conceivably would take a lie detector test.

"Yeah," he answered. "I don't know if they're good or bad."

After Monday's news conference will come the congressional hearing. Pettitte, former Yankees teammate Chuck Knoblauch and former Mets clubhouse attendant Kirk Radomski, who allegedly supplied McNamee with performance-enhancing drugs, also were asked to appear before the committee.

Lawyers for Clemens and McNamee have said their clients are willing to testify but Hardin wouldn't commit to the date.

Emery said he wanted to hear testimony from Clemens.

"If Congress calls him, he pretty much has to take the Fifth, and if he takes the Fifth, nobody will ever believe him again and all this effort has gone down the drain," Emery said. "And if he doesn't take the Fifth, it's very hard to imagine that a prosecutor isn't going to pursue this. So I think he's put himself in a terrible corner."

Clemens said his lawyer advised him not to speak with Mitchell, who spent 20 months on his investigation.

"If I would've known what this man, what Brian McNamee (had) said in this report, I would have been down there in a heartbeat to take care of it," Clemens said.

Only two active players, Jason Giambi and Frank Thomas, spoke with Mitchell, a Boston Red Sox director and a former Senate majority leader.

In excerpts of the CBS interview that were released Thursday, Clemens said McNamee injected him with vitamin B-12 and the painkiller lidocaine. In the full 14-minute broadcast, Clemens also said he was given an injection of toradol under the supervision of the New York Yankees.

McNamee told Mitchell he injected Clemens with steroids and HGH about 16 to 21 times during 1998, 2000 and 2001 — before baseball players and owners agreed to ban performance-enhancing substances.

Eighth on the career list with 354 wins, the 45-year-old Clemens said he was angered McNamee's accusations have been accepted as truth by some.

"It's hogwash for people to even assume this," Clemens said. "Twenty-four, 25 years, Mike. You'd think I'd get an inch of respect. An inch."

Clemens said the descriptions McNamee gave Mitchell of injections "never happened."

"If I have these needles and these steroids and all these drugs, where did I get 'em?" he said. "Where is the person out there (who) gave 'em to me? Please, please come forward."

FOX News' Catherine Donaldson-Evans and The Associated Press contributed to this report.