"We have no knowledge of [the grand jury] one way or the other," Rusty Hardin, one of Clemens's attorneys, said Monday morning. "All I have heard is rumors from people saying something. But we have had no contact with anyone about it, and have no idea.''
Federal agents also have interviewed friends and acquaintances of Clemens in Houston over the past year, and it is possible some of them could be invited to Washington.
A Houston training center owner, Shaun Kelley, told The Associated Press Monday that he had been questioned by the FBI last April and denied meeting Clemens or providing the pitcher or any of the pitcher's associates with illegal substances. Kelley said he employed Clemens's stepsister Bonnie Owens for about a year.
Kelley said neither he nor his lawyers had been contacted by the grand jury.
"It is just not fair for me, because they just come down here and throw me under the bus, and I lose half-a-million of business," Kelley said Monday in a telephone interview with the AP.
"I know in my heart I passed it," he said of the polygraph, "but the FBI is not known for admitting their mistakes."
Another possibility is former Clemens teammate Pettitte. He and another former New York Yankees teammate, Chuck Knoblauch, confirmed McNamee's testimony that they used performance-enhancing drugs when he was their trainer.
Pettitte provided a sworn affidavit to a congressional committee, in which he claimed Clemens told him nearly 10 years ago that he used growth hormone. Pressed to address Pettitte's statement during the committee hearing, Clemens said Pettitte had "misremembered."
The grand jury is also likely to consider DNA samples on used needles and bloody gauze pads McNamee turned over to federal prosecutors last January. McNamee's lawyers have claimed he used those needles and gauze pads while injecting Clemens with steroids and HGH. Clemens's side has called that evidence "manufactured."
McNamee's lawyer, Richard Emery, said Monday his client has not been called as a grand jury witness or received a subpoena. But he does expect McNamee to testify again.
"We will be cooperating. We've been in contact with the federal authorities for a year and a half," Emery said, according to The Associated Press. "We look forward to the results, which we fully expect will show that Brian has been telling the truth all along."
Additional evidence for jurors to review could come from Radomski, a former New York Mets clubhouse attendant who was a source of the performance-enhancing drugs that McNamee provided to a number of players. In July, Radomski turned over to federal investigators an overnight shipping receipt for a package of two kits of HGH that he sent after the 2002 season, in care of McNamee, to Clemens at the pitcher's Houston home.
"The investigators knew from day one that I sent a package to Clemens's house," Radomski told ESPN.com last summer after discovering he still had the receipt. "They knew before the Mitchell report was released and before Brian went before Congress. So, this is nothing new to them.
"I just couldn't find the receipt."
Federal agents raided Radomski's Long Island home in December 2005, uncovering evidence that he supplied anabolic steroids and other drugs to pro baseball players. Radomski said he knew the performance-enhancing drugs sold to McNamee were intended for his baseball-playing clients, though he didn't inquire about their identities.