Yamaha rider Rossi crashed heavily on lap four of the race after losing control of his bike at Turn 8.
He was stretchered off and taken to the medical centre and later to a local hospital for a CT scan, although the team reported he had not suffered any serious injuries.
Yamaha said Rossi suffered a concussion with a suspected loss of consciousness, but the CT scan ruled out any bleeding in the brain.
He will be under observation in the coming hours, but the team said there are no reasons for concern.
The next race takes place in Japan on October 12.