Joint MotoGP championship leader Jorge Lorenzo is doubtful for Sunday's Chinese Grand Prix after fracturing a bone in his left ankle.

Yamaha said the Spaniard was taken to hospital in Shanghai for a scan after being thrown off his bike in the day's first free practice session.

He then returned to the track but spent the rest of the day resting at the MotoGP clinic.

"His condition will be re-assessed in the morning before any decision is taken about riding," the team said.

Lorenzo, team mate to Italian Valentino Rossi and winner of the previous race in Portugal, is level with compatriot Dani Pedrosa on 61 points after three races.

MotoGP doctor Claudio Costa said the rider, in his first season in the top category, had re-fractured a bone in the middle of his left ankle and also suffered heavy bruising to his right ankle.

"The diagnosis shows the violence of the trauma he suffered to both his feet in the crash and Jorge now faces a very difficult task to participate in tomorrow's qualifying and Sunday's race," said Costa.

The practice session was Lorenzo's first since undergoing surgery on his right arm to deal with pain while he rides and he was on only his 10th lap when he lost control. The Spaniard turns 21 on Sunday.

"There is still a chance he might be able to ride. It will be a race full of suffering, pain and tears, but the riders are heroes and they are capable of doing things like this," Costa said.

Former champion Rossi set the fastest time in the combined practice sessions, with Australia's reigning champion Casey Stoner second on the timesheets for Ducati.

Watch all the action from Shanghai LIVE on Eurosport, with free practice from 06:00 in the morning on Friday, qualifying from 06:00 on Saturday and all three races on Sunday - starting with the 125s at 04:45 and ending with the MotoGP at 07:15!!

Reuters