WASHINGTON — Baseball star Roger Clemens is arguing he should be allowed to introduce evidence during his upcoming steroid trial that the leading witness against him raped an unconscious woman and lied to police investigating the assault.

The move is part of Clemens’ attempt to discredit his former trainer Brian McNamee, who was never charged in the assault investigation but admits he lied when questioned by Florida police in 2001. In a filing late Wednesday night, Clemens’ attorneys argued the experience gave McNamee a motive to falsely accuse Clemens of using drugs to save himself from becoming a target of a federal criminal investigation in 2007.

That’s the year McNamee told federal agents and investigators examining the role of performance-enhancing drugs in Major League Baseball that he repeatedly injected Clemens with steroids and human growth hormone. The standout pitcher has steadfastly refuted McNamee’s allegations and is going on trial next week on charges he lied to Congress about using drugs.

Prosecutors filed a motion last week asking U.S. District Judge Reggie Walton to restrict Clemens’ attorneys’ questioning of McNamee about the investigation during cross-examination or introducing evidence that the trainer assaulted the woman. Prosecutors said the issue could become a “sideshow” that would unfairly prejudice the jury against their leading witness.

The Florida investigation occurred in October 2001, when McNamee was an assistant strength and conditioning coach with the New York Yankees and had accompanied the team to a series against the Tampa Bay Devil Rays. one