Joshua Cooper, aged 21, of Osbaldwick, York, is wanted for recall to prison after breaching the terms of his release licence.
Cooper was sentenced to 24 months’ imprisonment in December 2011 for GBH after hitting a man with a wooden pole in Moor Monkton in June.
He was released on licence in August 2012, but is since suspected of committing a further assault.
Officers have been making enquiries throughout the city in an effort to trace Cooper and are urging the public to report any sightings of him.
He is described as white, around 5ft 8in tall, with a medium build, blue eyes and fair hair.
Detective Sergeant Mark Jackson, of York CID, said:
Joshua Cooper is in breach of his prison release licence and he will be well aware that we are looking for him.
We believe he is still in York and will be knocking on doors around the city until we find him.
By continuing to evade the police he is making life very difficult for himself and he will have a lot more questions to answer when we do catch up with him.
I am urging the public to contact the police or Crimestoppers if they know where Cooper is or see anyone matching his description.
If you can help officers with their enquiries, please contact North Yorkshire Police on 101 – select option 1 – and pass information to the Force Control Room.
If you prefer not to give your name, Crimestoppers can be contacted anonymously on 0800 555 111.
Please quote reference number 12130152717 when passing information about Joshua Cooper’s whereabouts.