Clemens, lawyer Rusty Hardin and others also weren't serious when they questioned McNamee's mental state, wrote attorney Joe Roden in the motion filed in federal court in Brooklyn, according to a report Thursday in the New York Daily News.
"They are part of the public battle of words between the two camps, and in no way suggest to the average reader that McNamee is actually mentally unfit," Roden wrote.
In addition, Roden said that the Clemens camp's claims that McNamee manufactured evidence do not constitute defamation.
McNamee, who said that he injected Clemens with steroids and human growth hormone while the pitcher was with the Blue Jays and Yankees from 1998 to 2001, turned over used syringes and bloody gauze pads to federal authorities after a congressional hearing last year.
"Clemens never used steroids or HGH," Roden said. "Refuting false evidence is not defamation."
McNamee's attorney, Richard Emery, countered with a motion opposing a dismissal.
"There is no question that the statements from Clemens and his lawyer and spokesmen are a serious and nasty attack on Brian, accusing him of being a criminal and mentally unstable," Emery said. "That is part of the defamation here."
Bobbie Dittmeier is an editor/producer for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.