The 23-year-old was targeted as he walked along Eldon Street, towards West Street in Sheffield city centre, at 3am on Tuesday, January 21.
South Yorkshire Police said he was approached by a group of around seven men.
He was punched in the head a number of times and one of the men produced a flick knife whilst making demands for his property.
The victim managed to break free and run to safety.
Four men were arrested in connection to the incident around an hour later in Select and Save on Arundel Gate.
They have been bailed pending further enquiries.
CCTV footage has now been released of a man who police believe could hold vital information about the incident.
Anyone with information should call 101 and quote crime reference number 14/20488/20.