According to the report, a female employee at Harrah's Casino in Lake Tahoe filed a civil suit against Roethlisberger for the alleged actions.
Through his lawyer David Cornwell, Roethlisberger denied the allegations.
"Ben has never sexually assaulted anyone," Cornwell said in a statement. "The timing of the lawsuit and the absence of a criminal complaint and a criminal investigation are the most compelling evidence of the absence of any criminal conduct. If an investigation is commenced, Ben will cooperate fully and Ben will be fully exonerated."
The AP reported that the incident took place in July of 2008.
Steelers spokesman Dave Lockett told ProFootballTalk.com that the team cannot comment publicly, but the Steelers have "been told Ben's side of the story and we fully support him at this time."
PFT also claims to have acquired a "full and complete and reliable" copy of the complaint.
