Hinchcliffe suddenly pulled off the road course at Indianapolis Motor Speedway following a restart and could be seen holding his head with both hands as he exited his car. The Oakville, Ont., native was taken from the track on a stretcher and transported to a hospital.
IndyCar said Saturday night he had been released from the hospital after a CT scan on his head and neck. He must be medically cleared by IndyCar to drive, and the waiting time is usually a minimum of seven days.
IMS opens Sunday for practice for the Indianapolis 500. Qualifications begin next Saturday and the race is May 25. Andretti Autosport said EJ Viso would be on standby for Hinchcliffe.
"I'm a little stiff and sore and I'd love to be back in the car tomorrow, but I suppose I should probably let the doctors make that decision," Hinchcliffe said in a statement.