The attack happened in Imperial Street off the Ravenhill Road.
According to the PSNI, officers received a report that at around 2am, a man aged in his 40’s, whilst out with his dog, was approached by a male wearing a black hooded top.
The male reportedly stabbed the man in his back and then held the knife to his throat.
A scuffle took place and the male made off on foot.
The knife believed to have been used in the attack has been seized for forensic examination.
The injured man was taken to hospital and treated for injuries that are not thought to be life threatening.
Detective Chief Inspector Gary Reid said: “I am appealing for anyone with any information about this incident to contact CID at Musgrave on 101.
“Information can also be passed anonymously through the independent charity Crimestoppers on 0800 555 111.”