The incident happened at a residence on Knox Street around 12:50 a.m.
Police said the 24-year-old victim was shot while responding to a knock at the door.
The suspect fled the scene, and police have yet to make an arrest.
The victim, who is known to police, was taken to hospital. Authorities do not fear for his life.
A second person in the apartment at the time of the shooting was unharmed.