Houston Astros pitchers Roger Clemens, left, and Andy Pettitte line...

Houston Astros pitchers Roger Clemens, left, and Andy Pettitte line up for opening day introductions before their game against the San Francisco Giants. (April 5, 2004) Credit: AP

WASHINGTON -- Yankees pitcher Andy Pettitte took the stand Tuesday in the Roger Clemens perjury trial to testify that Clemens, his friend and mentor, told him in 1999 or 2000 that he had taken human growth hormone to aid his physical recovery.

"We were working out at Roger's house in the gym," Pettitte told jurors, under questioning by Assistant U.S. Attorney Steven Durham.

"Roger had mentioned to me that he had taken HGH and that it could help with recovery. That's really all I remember about the conversation."

Asked by Clemens attorney Michael Attanasio whether the exchange was a "passing comment" during a vigorous workout, Pettitte agreed. "Yes, I would say so," he said. Pettitte said he couldn't remember the context of the conversation.

Pettitte, considered a key witness in the government's case that Clemens lied to Congress in 2008 when he denied taking performance-enhancing drugs, said he had never heard of human growth hormone until then.

He also admitted he used HGH himself on two days in 2002 and once in 2004, and said it did not seem to help him. "I wish I never would have," Pettitte said. "If I hadn't ever done it, I wouldn't be here today."

Pettitte took the stand just before noon and gave short, often terse, answers for the rest of the day. His testimony will resume Wednesday.

Pettitte did not look at Clemens throughout the proceedings, except when Durham asked him to point him out. He identified Clemens as the man "in the suit with the greenish tie." Clemens, dressed in a black suit, showed no emotion as he watched Pettitte testify.

Though Pettitte called Clemens "a friend" and mentor, he acknowledged he hadn't spoken to him in "a long time," on the advice of his lawyers.

Pettitte also testified about a second conversation he said he had with Clemens, which he said occurred during spring training in 2005 in the kitchen at the Houston Astros facility in Kissimmee, Fla.

Under questioning from Durham, Pettitte recalled becoming nervous that a reporter might ask him whether he had used performance-enhancing drugs, so he went to Clemens.

"I asked him if anyone would ask him if he used performance-enhancing drugs, what are you going to say?" Pettitte said. "He said, 'What are you talking about?' "

Clemens said he didn't tell him he had used HGH -- his wife had. "Obviously I was a little flustered," Pettitte said about Clemens contradicting his memory. Pettitte said he thought to himself, "Well, no good asking him or talking to him about this now."

Asked by Durham about Brian McNamee, Clemens' former trainer and accuser, Pettitte said he still considered him a friend and said, "He did a great job training me." Attanasio was asking Pettitte about the Yankees' firing of McNamee when court adjourned for the day.

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