The collision occurred on Lakeshore Road East, east of Cawthra Road, around 1:30 p.m.
Police said a 38-year-old woman was running in the lane of the curb when the driver hit her.
He was taken to a local hospital with serious injuries.
Police said the driver fled.  On Sunday, police released a description of the vehicle, which is a newer model of a dark minivan.
Police believe that the vehicle was damaged on the passenger side.
Anyone who has seen the collision or has information about the suspect or his vehicle should contact the Office of Major Conflict at 905-453-2121 ext.  3710 or Crime Stoppers anonymously at 1-800-222-TIPS (8477).