A motion filed Friday evening by Clemens' attorneys argues the indictment is vague and contains too many separate accusations of lying in one count.
The motion states that that could cause jurors who don't unanimously agree to still convict Clemens in violation of his constitutional rights.
For instance, the motion says some jurors might vote to convict, believing Clemens lied about using human growth hormones but not steroids, while others might vote to convict believing the opposite. The attorneys say the Constitution requires that any conviction be based on a unanimous verdict for each element of the charged offense.
"A trial of the government's laundry list obstruction count would fundamentally prejudice Mr. Clemens," his attorneys wrote.
Clemens is accused of lying to the House Committee On Oversight and Government Reform during a deposition and subsequent hearing in February 2008. His attorneys say the indictment accuses the former pitcher of 15 distinct false statements that would require different proof, witnesses and evidence in "a single kitchen sink count."
"As an example, the government will need to present completely different evidence to prove that Mr. Clemens misled the House committee about the general availability of Vitamin B-12 in Major League clubhouses than it will to prove that Mr. Clemens lied about visiting a teammate's house for a barbecue nine years earlier," the motion read.
Clemens attorneys said that even if the judge rejects their motion, he reserves the right to challenge the false testimony charge based on the "ambiguous questions" that were posed to him.
Earlier Friday, prosecutors said they wanted to prevent Clemens' lawyer from cross-examining his former teammate Andy Pettitte over claims that Clemens lied about using performance-enhancing drugs.
Prosecutors filed a motion arguing that defense attorney Rusty Hardin has a conflict of interest because he briefly advised Pettitte along with Clemens in early December 2007 just before the release of a report alleging both players used human growth hormone.
Clemens has steadfastly denied the allegations and has long fought any suggestion that he cheated during a 23-season career that ended with 354 wins, 4,672 strikeouts and seven Cy Young awards.
But Pettitte admitted using the drug and said Clemens admitted privately he did as well.
Prosecutors intend to call Pettitte as a witness in the trial scheduled for this summer. They said Hardin's conflict can be resolved if another attorney representing Clemens cross examines Pettitte, but asked a judge to hold a hearing on the matter.