He was attacked at about 7.35 pm near a Tesco supermarket on the Castlewellan Road in Newcastle, Co Down.
The victim, who is in his 40s, has been taken to the emergency department at the Royal Victoria Hospital for treatment to his injuries.
A man has been arrested in connection with the incident and is being held on suspicion of attempted murder.
Investigating officer Det Insp Brian Foster: “This occurred at quite a busy time.
“Therefore, I would ask anyone who was in the area at the time to contact detectives at Downpatrick police station on the non emergency number 101.”