Police used a Taser to subdue Whitner, who was arrested for aggravated disorderly conduct and resisting arrest.
Whitner was released from his holding cell Saturday afternoon. Police Lt. Thomas Stacho said charges have not been filed.
"I regret the incident that occurred last evening," Whitner said in a statement released Saturday. "It's not how I wish to conduct myself. And I apologize to all those involved."
A statement from the Cleveland Police Department alleged a brawl erupted outside the club at about 3 a.m. As off-duty officers tried to restore order, Whitner aggressively forced his way into an area where he was told not to go. Officers temporarily restrained him before he broke free and squared off to fight.
"Whitner began swinging his arms in a violent manner and, when restrained by officers, he broke free and took a fighting stance," the Cleveland Police statement read. "An officer then deployed his Taser on Whitner, debilitating him enough that officers were able to place him in handcuffs."
This isn't the first time Whitner, 23, has been in trouble with the law. In 2006, he was arrested for non-criminal harassment of his live-in girlfriend in suburban Buffalo.
"We are aware of the report," Bills spokesman Scott Berchtold said in a statement on the team's Web site. "At the present time we are attempting to gather all of the facts and will defer comment until that process is completed."
Whitner's arrest is the latest in a troubling sequence of offseason event for the Bills.
Three days ago, Pro Bowl running back Marshawn Lynch received a three-game suspension for two transgressions in a nine-month span. He was the driver in a hit-and-run incident last summer in Buffalo but escaped with a traffic ticket.
Lynch's latest incident was a Feb. 11 arrest in Culver City, Calif. He was charged with carrying a concealed, loaded and unregistered 9-mm handgun. He pleaded guilty to one of the misdemeanor charges in exchange for having the other two dropped. He was sentenced to three years' probation and 80 hours of community service.
Safety Ko Simpson was arrested for disorderly conduct at 2 a.m. ET on New Year's Day outside a bar in his hometown of Rock Hill, S.C.
Police were in the process of arresting two of Simpson's friends for disorderly conduct, while he kept yelling, "I'm Ko Simpson with the Buffalo Bills. I am worth millions!'' Police claim they asked Simpson to leave the scene several times, but he kept screaming.
"You don't like any issues that happen in our business to our players in particular," Bills coach Dick Jauron said March 24 at the NFL owners' meeting in Dana Point, Calif., referring to Lynch and Simpson. "It's hard because you certainly don't condone anything that happened.
"You also know that young men make errors in judgment. So you have to help them correct it and learn from it and mature from it and hope people don't destroy their lives by some silly mistake. You hope they limit their mistakes to ones that don't hurt other people badly and determine their lives."
Tim Graham covers the NFL for ESPN.com.