The accident happened after a police car was involved in a pursuit of a vehicle along Queen Street.
A Toronto EMS spokesperson told CBC News that paramedics were called to the scene at Queen Street West and Augusta Avenue, just before 4:30 p.m.
The victim, a cyclist, had her leg trapped between the car and a newspaper box. She was taken to hospital with what appeared to be severe injury to one leg.
The province's Special Investigations Unit has been called in to investigate.
The SIU investigates all incidents involving police that result in death, serious injury or in cases when allegations of sexual assault are raised.