The Special Investigations Unit said in a news release that at about 8 p.m. ET Tuesday, Peel Regional Police officers on Absolute Avenue, near Burnhamthorpe Road and Hurontario Street, had tried to arrest a person in a vehicle.
The vehicle drove onto the sidewalk, struck the 46-year-old man, and fled.
The injured man was taken to St. Michael's Hospital with head injuries, internal injuries and a fractured leg.
The SIU has assigned seven people to the case, including a collision reconstruction expert.
Anyone with information about the incident is be asked to call (416) 622-1957.
The SIU investigates all incidents involving police that result in death or serious injuries.