A 48-year-old was arrested in connection with what Humberside Police say was a "serious assault" in Goole on Saturday April 14.
It happened around midnight on Aire Street between two men. One fell backwards and hit his head and is still in hospital with head injuries.
The suspect has been released under investigation but police are appealing for any witnesses to come forward or anyone who may have information.
Quote reference number 16/46432/18.