The incident between the 51-year-old Moyes and a 23-year-old man reportedly happened on Thursday in northern England.
When asked about the incident involving Moyes, police said they were "investigating a report of an assault at the Emporium wine bar in Clitheroe. Officers attended the bar at about 10 p.m. yesterday and it was reported that a 23-year-old local man had been assaulted by a 51-year old man."
Police said the victim did not require hospital treatment and that "no-one has been arrested at this stage."
Moyes was fired by United in April following a disappointing 10-month tenure.