MILLEDGEVILLE, Ga. — For the second time in a year, Pittsburgh Steelers quarterback Ben Roethlisberger is being accused of sexual misconduct, with police investigating him Saturday for an alleged assault at a nightclub in a Georgia college town.

Police in Milledgeville were examining the claim of a 20-year-old student, who told an officer that Roethlisberger sexually assaulted her early Friday. The police department had no plans to comment further until Monday at the earliest.

The case comes as Roethlisberger faces a lawsuit filed last July by a woman who says he raped her in 2008 at a Lake Tahoe hotel and casino, an allegation he strongly denies. Roethlisberger, who was not in custody, has not been criminally charged in either case and has claimed counter-damages in the lawsuit.

Still, to hear it on the airwaves in Pittsburgh, this latest situation seems to have shaken fans of the star quarterback, a man who has never hidden the fact he enjoys the nightlife. He has been spotted gambling in Las Vegas and is sometimes seen in public with small groups of friends and bodyguards.

The latest accusation came early Friday in downtown Milledgeville, about 85 miles southeast of Atlanta and about 30 miles south of the lake home the player owns. Roethlisberger, who turned 28 on Tuesday, and two or three friends went to Buffington's bar earlier Thursday night to watch the University of Pittsburgh men's college basketball game, said Paul Kurcikevicus, a 24-year-old college student.

He said the group was friendly, at first joking that Roethlisberger was not the NFL player. Kurcikevicus said Roethlisberger bought shots for him and some other people in the bar: "O-Bombs," a mixture of energy drink and flavored rum.

The group later went to The Brick restaurant nearby, owner Frank Pendergrast said.

"He was very polite with everybody," Pendergrast said. "He was down here from about 11:30 until about 1:30 having a good time, talking to a lot of people. Looked like he was signing autographs and letting people take pictures. Other than that, it was really uneventful."

Roethlisberger was later seen at Capital City, a popular nightclub for students at Georgia College & State University in Milledgeville.

One patron at the bar on Friday night, 21-year-old college student Brandon Harris, said he saw Roethlisberger come in the night before with two or three big men who were keeping other club goers away. Harris said the group went into a curtained VIP area in the back of the club, and some women were let inside.

Amber Hanley, a 21-year-old college student, said she and a few friends were also in the VIP area with Roethlisberger. She said she asked the quarterback to take a photo with her friend, who was a fan, but he seemed disappointed that's all she wanted. Hanley said she rolled her eyes, and Roethlisberger called her an expletive and walked away. Later, Roethlisberger was aggressively hitting on another girl, Hanley said.

Deputy Police Chief Richard Malone said Friday that Roethlisberger had been with three other people who were mingling with another group that included the alleged victim. Malone said the woman and her party contacted a nearby police officer following the alleged assault.

"He's been identified as being at the scene and there are allegations naming him as the perpetrator," Malone said. The nature of the assault was not described, but Malone did say it was being termed a sexual assault, not a rape.

Roethlisberger and the alleged victim were interviewed and the woman was taken to a hospital, where she was treated and released, Malone said. The woman was not identified by police and The Associated Press does not generally identify possible victims of sexual abuse.

Police said Roethlisberger and his attorney were cooperating with investigators. He was not in custody.

The player's agent, Ryan Tollner, said in a statement he was skeptical of the motive of the alleged victim in Milledgeville because of the previous Lake Tahoe allegations. Steelers spokesman Dave Lockett said the team was gathering information and had no comment.

As Pittsburgh's first-round draft pick out of Miami of Ohio in 2004, Roethlisberger led the Steelers to Super Bowl victories in 2006 and 2009. He has frequently donated time and money to charities, and his charitable foundation awards a police dog to a department near every Steelers road opponent.

However, with his championships and $102 million contract have come several off-the-field problems. In 2006, he defied his coach's orders and rode his motorcycle without a helmet — and wound up with a concussion, broken jaw and other injuries after a wreck.

And while Roethlisberger has a reputation for patiently signing autographs and posing for pictures while out in public, he also is known for occasionally inelegant behavior in Pittsburgh. Early in his career, he was photographed — obviously after imbibing in alcohol — wearing a T-shirt reading "Drink Like a Champion." Restaurant owners in Pittsburgh have complained he has tried to skip out on bills, arguing he brought business to the establishment.

The public largely supported him when he was accused of sexual assault in Nevada. But radio shows in Pittsburgh have been flooded with calls since Friday's allegation — few of them sympathetic, with many wondering if the new case indicates a troubling pattern of behavior.