Shortly before 8pm on November 21 a man was found in the road on Westbourne Grove.
North Yorkshire Police is appealing for information or anyone who may have witnessed the assault to establish the full circumstances of the incident.
In particular, officers would like to speak to a woman described as wearing a red coat who may have witnessed the incident but left the scene before police arrived.
Anyone with information that could assist the investigation should contact North Yorkshire Police by calling 101. If you wish to remain anonymous, you can pass information to Crimestoppers on 0800 555 111.
Please quote the North Yorkshire Police reference number 12190214427.