A 15-year-old boy was approached by a man on Old Birmingham Road at around 6pm on 1 August.
The man demanded the boy hand over his bike before attacking him with a large bladed weapon.
The suspect then fled the scene with the bike and the boy was left with a serious hand injury.
The boy was then taken to hospital for further treatment.
It is believed the man in the image was in the area at the time of the incident and may have information which could assist officers with their investigation.