It happened around 2am and involved a collision with what is described as a small, dark vehicle in London Road at the junction with Acacia Road.
He was taken to hospital with serious injuries.
Police are now asking anyone who has any information about the incident to call 101 quoting reference number 24 of 20 January. You can also give information online.
Alternatively, you can also call Crimestoppers, anonymously, on 0800 555 111.