The Test cricketer, 50, was allegedly confronted by a 46-year-old man in the suburb of Cremorne on April 14. Two other men then appeared and forced him into a car.
New South Wales police said Mr MacGill, who played 44 Tests for Australia, was driven to a property in Bringelly, 30 miles away.
The kidnappers then assaulted and threatened the leg spinner with a firearm, police said.
After about an hour, he was driven to the south-west suburb of Belmore and released.