Police said the knife occurred in the area of Peter and Adelaide Streets shortly after 2 p.m.
Two people were fighting, according to police, when one of them stabbed a knife and stabbed the other.
By the time police arrived, the victim had already left the area, police said. Now they are looking for him as they worry about his safety.
Police released a photo of the victim, asking for the public’s help in identifying him.
Described as six feet tall with slender build and short black braided hair. He was wearing blue jogging pants and a black sweater.
Police ask anyone with information to contact them at 416-808-5200 or Crime Stoppers anonymously at 416-222-TIPS (8477).