The incident occurred in the early hours of Sunday, December 19th.
Sergeant Knox said: “Between midnight and 1am a 48-year-old man was assaulted.
“We understand this to have taken place somewhere between the Northland Road junction with Northland Avenue in the city.
“The victim was taken to hospital for treatment to his injuries and has sustained a fractured skull, hip, jaw and nose.
“We are appealing for any persons who may have been in the area and witnessed anything suspicious or who perhaps might have dash-cam footage to contact us on reference number 180 19/12/21.
“We are especially keen to speak with anyone who have witnessed a group of young males in the area of Northland Avenue at approximately 12.30am on the morning of December 19th to contact us.”
Alternatively, police advised, you can submit a report online using the non-emergency reporting form via http://www.psni.police.uk/makeareport/
You can also contact Crimestoppers anonymously on 0800 555 111 or online at http://crimestoppers-uk.org/