It occurred at a flat in Gisburn House, Acomb, just after 7.30pm on Tuesday 6 December 2011. Two men broke into the flat and assaulted the 23-year-old man who lives there with a metal implement.
The man suffered a head injury which, although not life threatening, has required treatment as in patient at York District Hospital.
A 21-year-old man was arrested on Pateley Place and a 23-year-old man was arrested at a local address in connection with the incident.
DC Fionna McEwan, of York CID said:
I am particularly keen to speak to anyone who may have seen a man running along Front Street in the direction of Pateley Place between 7.30pm and 8pm.
Anyone who can help the police with their enquiries is urged to contact DC Fionna McEwan at York police station on 0845 60 60 24 7. Press option 2 and ask for Fionna McEwan by name.
Or call Crimestoppers anonymously on 0800 555 111 quoting reference number 12110205870.