Police were called to The Sportsman pub in Bolton, on Thursday night where the 28-year-old midfielder was said to have been involved in a "disturbance".
A spokesman for Greater Manchester Police said: "Officers were called around 23.15pm on Thursday, May 20, to Darwen Road, Bolton, to a report of a disturbance.
"Officers attended and enquiries established two males had been involved in a fight with one another. The males fled the scene prior to police arrival.
"No arrests have been made."
The pub's landlord David Brown, who described the incident as "violent" and "unpleasant", said: "I'm speaking with the chairman and the player. We're just dealing with it to see where it goes."
Brian Caldwell, the club's chief executive, said: "We are aware of the alleged incident and it is currently under internal investigation."