Brian McNamee has said he injected Clemens with steroids and human growth hormone in 1998, 2000 and 2001. Clemens is accused of lying to Congress in 2008 when he denied using those drugs.
McNamee, wearing a tan suit and speaking softly in a thick New York accent, began his testimony with questions that focused on his job history. The case broke for lunch before he got into anything about Clemens.
McNamee, Clemens' former strength coach, says he saved items that he used while injecting Clemens with performance-enhancing drugs, including gauze, tissues, syringes, cotton balls and needles. Prosecutors say they have evidence that some of the materials tested positive for the drugs as well as Clemens' DNA.
Clemens' lawyers have said they will contend that the items saved by McNamee have been tainted and contaminated because they were stored so haphazardly. They refer to the collection as a ''mixed-up hodgepodge of garbage.'' Clemens insists that McNamee injected him with vitamin B12 and the anesthetic lidocaine.
McNamee and the jury arrived in the courtroom after Clemens lost his attempt to bring in information from McNamee's divorce. U.S. District Judge Reggie Walton granted motions filed by McNamee and his estranged wife's law firm to quash a Clemens subpoena for divorce records. The judge called the subpoena a ''fishing expedition.''
Walton also rejected a defense motion to strike Andy Pettitte's testimony about a contested conversation a dozen years ago about human growth hormone.