Rookie star Jorge Lorenzo's ankle injuries are more serious than originally thought following his spectacular crash in practice for the Chinese Grand Prix at the weekend.

Tests in Barcelona revealed that the 21-year-old Yamaha rider had fractured his right as well as left ankle, which also had ligament damage.

Spaniard Lorenzo finished fourth in Sunday's race despite the injuries and is in second place in the world championship standings behind countryman Dani Pedrosa.

He has been a sensation since stepping up from the 250cc category, which he won in 2007.

Lorenzo underwent surgery on his forearm to correct a longstanding problem in the weeks before the race in China.

Five-times MotoGP champion Valentino Rossi, team-mate of Lorenzo, won in Shanghai - ending his longest streak without a victory.

Reuters