Pettitte later admitted using human growth hormone. He also told congressional lawyers that Clemens informed him nearly a decade ago he had used HGH.
U.S. District Judge Keith P. Ellison ruled Tuesday that since McNamee is not a former client of Hardin, he has no standing to ask for his disqualification. Only Pettitte would be able to make such a challenge and he has chosen not to at this time, Ellison wrote in a 13-page order.
Clemens was given 20 days to respond to McNamee's motion to dismiss the lawsuit.
Richard Emery, one of McNamee's lawyers, has repeatedly said Hardin was selecting legal strategies that were assisting McNamee's cause.
"Many people have told me that I was silly to file this motion because Rusty is my best friend. And now he's going to have a chance to prove his friendship," Emery said.