In a video obtained by TMZ, a man said to be McCoy is seeing throwing multiple punches.
The fight left two off-duty police officers injured, one with a broken nose and broken ribs and the other with a possible skull fracture.
Philadelphia police have reportedly wrapped up their investigation and have turned over their findings to the district attorney's office, which is reviewing it for potential charges.
McCoy has already hired defense attorney Jack McMahon to represent him, ESPN reported.
The incident occurred early Sunday morning after an argument broke out between McCoy's party and the officers over a bottle of champagne.
After one 40-year-old officer was knocked to the ground, he was punched, kicked and stomped multiple times on his body and head, police said Monday.
When the second officer, also 40, intervened with security guards, he was also injured, police said. All were ejected from the club.
One officer had a broken nose, broken ribs and a sprained thumb and remained hospitalized, police said, while the second received stitches and had a possible skull fracture.
"Certainly over a bottle of champagne, nothing warrants an assault like this," police Lt. John Stanford said.
A person familiar with the investigation confirmed to The Associated Press that McCoy was one of the four men under investigation. He spoke on condition of anonymity because he was not authorized to publicly discuss the case.
McCoy played for the Bills last season after being traded from the Philadelphia Eagles, where he played for six seasons.
The Bills released a statement Monday saying they were aware of the report and were gathering information.
Police said they did not want to publicly identify the four suspects until arrest warrants are approved, though they said at least some had NFL connections.
The two officers did not identify themselves as policemen to their alleged attackers, Stanford said.
The fight over the bottle of champagne appeared to result from a misunderstanding. Stanford said a member of the football players' party thought a bottle belonged to his group but receipts showed it did not.
According to a police incident report obtained by The Philadelphia Inquirer and KYW-TV, the incident occurred at the Recess Lounge in Philadelphia's Old City neighborhood.
(TM and © Copyright 2016 CBS Radio Inc. and its relevant subsidiaries. CBS RADIO and EYE Logo TM and Copyright 2016 CBS Broadcasting Inc. Used under license. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.)
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