The 59-year-old was walking along Bailey Street, near Woodings Yard in Stafford, at around 3am.
The victim was approached from behind and assaulted while offenders attempted to steal his watch.
While the watch was not taken, the man suffered minor injuries to his head and arms.
Officers are now keen to trace a passer-by, who helped the victim make his way home, as they may be able to help detectives with their inquiries.
The incident happened on Saturday, July 30.
Anyone who was in the area at the time, or has any information or relevant dashcam footage, is asked to contact Staffordshire Police on Facebook or Twitter or call 101, quoting incident number 273 of 30 July.