Citing two unidentified sources familiar with the investigation, The Washington Post reported Tuesday that the DNA results are preliminary and subject to verification tests. The newspaper said Clemens voluntarily gave a DNA sample to federal authorities, according to the sources, and it still remains to be determined whether the syringes ever contained steroids or human growth hormone.

The test results could prove important to the investigation into whether Clemens lied under oath to Congress last year when he denied using steroids or HGH.

Prosecutors have asked a federal grand jury in Washington to decide whether to indict the seven-time Cy Young Award winner. Brian McNamee 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 HGH from 1998-2001.

Clemens' lawyer, Rusty Hardin, told the Post that the DNA testing "won't matter at all."

"It will still be evidence fabricated by McNamee," Hardin was quoted as saying. "I would be dumbfounded if any responsible person ever found this to be reliable or credible evidence in any way."