Casey Stoner has suffered multiple injuries in a sickening high-speed crash at the Suzuka 8-Hours endurance race in Japan.

The Australian MotoGP champion was riding for the Musashi Honda team when he missed a turn and careered off the track, flying off his bike before tumbling to a halt on the grass verge.

The 29-year-old suffered a broken shoulder blade and fractured tibia in the smash but was lucky to avoid more serious injury.

He later tweeted a photo of himself in hospital with a sling on his arm and a cast on his leg, and apologised to his team.