Authorities in Georgia say Pittsburgh Steelers quarterback Ben Roethlisberger is being investigated in an allegation of sexual assault.

Police say the incident occurred early Friday at the Capital City nightclub in Milledgeville, about 135 kilometres southeast of Atlanta. The National Football League player owns a home nearby.

The player and some of his friends were seen visiting some local restaurants and bars earlier Thursday night.

Separately, Roethlisberger has been sued by a woman who claims he raped her in 2008 at a Lake Tahoe hotel. The Steelers star denies those allegations and has asked for counter-damages.

Agent Ryan Tollner says "given the prior accusation against Ben, we are skeptical of motive, but we will continue to co-operate with everyone involved."

Roethlisberger, who turned 28 last week, has led the Steelers to two Super Bowl championships in his six seasons as starting quarterback, but there have been some problems off the field.

He suffered a concussion and required surgery for severe facial injuries in 2006 after an off-season motorcycle crash in which he was not wearing a helmet.

A Reno casino director in 2009 accused Roethlisberger of rape, filing a civil suit in connection with events following a celebrity golf tournament the previous year. She later filed a motion to dismiss her suit.