Scott Willis and his partner, Stacy Law, were targeted as they walked along Greenland Way, Darnall, after a drink in a pub on Christmas Eve.
The couple, who had Scott's daughter with them, were ambushed by two men.
Scott, aged 44, suffered a head injury and Stacy had a ring torn from her finger in the incident a 10.30pm on Saturday, December 24.
A South Yorkshire Police spokeswoman said: "It has been reported at around 10.30pm on Saturday, December 24, a 44-year-old man was walking along Greenland Way with his daughter and girlfriend, when he was approached by a group of men and hit in the face.
Rose House pub Walkley: Sheffield landlady pledges to stay open after windows smashed in two attacks
Sheffield father poured petrol over daughter and tried to set her on fire
Sheffield shooting: Three men charged after man shot in broad daylight in Manor area
Police incident Woodhouse Sheffield: Two men and a woman injured after large fight breaks out on Market Square
Staniforth Road Darnall: Man injured as van is smashed up in front of stunned onlookers in Sheffield
"The man received cuts and bruise to his eye in the reported attack and was treated by paramedics for his injuries."
Call South Yorkshire Police on 101 or Crimestoppers on 0800 555111 quoting incident 1,182 of December 24.
Manundergoes surgery after being knocked unconscious in robbery outside Sheffield nightclubPolice seek drivers who saw fatal Boxing Day crash in KillamarshWEATHER: Sheffield set for a cloudy daySouth Yorkshire ambulance bosses urge people to think twice before dialling 999 on New Year's Eve22 stars that died in 2016 but didn't get the biggest headlinesDownload The Star's mobile app now for FREEGet all the latest Owls statsGet all the latest Blades stats