BRNO, Czech Republic -- World champion Casey Stoner will miss Sunday's Czech MotoGP due to an ankle injury which could threaten his overall title defense.
Stoner was hurt during qualifying for the Indianapolis Grand Prix on Saturday, sustaining multiple chip fractures and four torn ligaments in his right ankle during a hard crash.
Despite the injury, Stoner was cleared for the race and finished fourth.
A statement on the official Moto GP website said Thursday the 26-year-old arrived in Brno but would leave later for Australia to undergo surgery early next week.
It is not clear when Stoner will return to racing.
Stoner is currently third in the MotoGP standings with 186 points, 39 behind leading Jorge Lorenzo, with seven races to go. He had already announced he'll retire after this season.