The incident happened more than two months ago but West Yorkshire Police have only just released images they hope will lead to him being identified.
The incident is said to have happened in the early hours of the morning on Saturday November 3 in a bar in Bradford.
A man in his forties suffered a broken jaw and damage to his teeth.
Anyone who can assist in identifying him is asked to contact Bradford District CID on 101, quoting crime reference 13180551463, or use the live chat facility on the West Yorkshire Police website.
Information can also be reported to the independent charity Crimestoppers on 0800 555 111.