Davide Rigon has been taken to hospital with suspected multiple fractures to his left foot and ankle after a crash in Sunday's second GP2 race at Istanbul.
The Italian was involved in a serious accident when Julian Leal clipped the back of his car as he tried to switch from the inside to the outside while trying to pass Rigon on the pit straight.
The crash sent Rigon's Coloni car into the pit wall and then across the track, and a piece of suspension went through the chassis, causing the injury to his foot.
Team boss Paolo Coloni said: "It looks very bad. It is not just one bone that is broken, so I think it is very serious.
"Davide has gone straight to hospital for surgery. If it is as bad as we think, then it's bad news for his season."