Tech 3 Racing Team rider Bradley Smith is out of the Moto2 race in Malaysia after suffering a broken left collarbone and chest contusion.
Smith crashed on the first lap of practice at Sepang when a freak burst of rain caused Jules Cluzel, Marc Marquez and Smith to crash at turn 10.
The 20-year-old high sided and hit Marquez as he slid in the gravel trap.
Oxford-born Smith was taken to hospital in Kuala Lumpur for a CAT scan and was asked to stay overnight.
Smith recently signed a deal to race in the MotoGP World Championship in 2013 and 2014.
The 20-year-old will race for Monster Yamaha Tech 3 team when he switches to MotoGP.
He finished 18th in his last race at Phillip Island and is currently seventh in the overall standings.
His injury means he could have ridden for the last time this season.