The incident happened at around 10pm on February 14 after the Europa League match between Celtic and Valencia finished at Celtic Park.
The man is described as being about 6ft tall, of slim build with dark hair and pointed features.
He was wearing a distinctive dark tracksuit with reflective white flashes on the legs and shoulders, a white logo on the chest and black trainers.
Inspector Iain Sibbald, of Greater Glasgow Alcohol and Violence Reduction Unit, urged anyone with information about the identity of the man in the photograph to contact him.
He said: “Anyone with information about the incident or who recognises the man should get in touch with me at London Road Police Office via 101.”
Information can also be provided anonymously to Crimestoppers on 0800 555 111.