NEW YORK — Brian McNamee says he couldn't risk lying to federal agents when they asked him about Roger Clemens and performance-enhancing drugs.

McNamee, the pitcher's former trainer, broke his silence by appearing on "The Howard Stern Show" on Monday morning.

"You just think of circumstances," he said. "It wasn't worth that risk of that being over my head for six years — that's the term they have to investigate you and convene a grand jury."

McNamee declined comment after leaving Stern's studio. He has told federal agents, baseball investigator George Mitchell and a House of Representatives committee that he injected Clemens more than a dozen times with steroids and human growth hormone from 1998-01.

McNamee said he doesn't believe he violated Clemens' loyalty by confessing to authorities. His business was doing well independent of his work with the pitcher, McNamee said, though he acknowledged his affiliation with Clemens helped his credibility.

"It wasn't a financial thing for me to work with Clemens," McNamee said.

"Were we friends?" McNamee added. "I think there was a little bit of an arm's distance we kept."