Lawyers acting for Everton midfielder Ross Barkley say their client "was the victim of an unprovoked attack by a stranger" on Sunday night.
Merseyside Police had confirmed earlier on Monday that they were making enquiries into a video which emerged on social media and showed a person resembling Barkley being punched in a Liverpool bar.
The CCTV video showed him speaking to another man before he then appeared to be punched in the face and quickly disappeared out of shot.
Sky sources understand Barkley trained as normal with the rest of the Everton squad on Monday and has suffered no lasting damage.
A statement read: "We can confirm that Ross was the victim of an unprovoked attack by a stranger who approached him on Sunday evening."
The incident took place in the hours after 23-year-old Barkley had played in Everton's 4-2 win over Leicester City at Goodison Park.
"Merseyside Police is aware of footage online reportedly showing an assault in a bar in Liverpool city centre," read a statement.
"No report of an assault has been received but officers are making enquiries to establish the circumstances of the incident."
A spokesperson for the bar in question, Santa Chupitos, confirmed on Monday that an employee who leaked footage of the incident will be dismissed.
"We take the privacy of anyone in our bar extremely seriously and what has happened is very disappointing," the spokesman said.
"In the first instance it's very rare that any altercations happen in the venue. We're a friendly bar and this is not something which happens regularly. It's very much an isolated incident.
"We'll work with the authorities to help in any way we can now.
"We've found out how the footage was made public and acted quickly to remove the person responsible from the company.
"He will be losing his job."