A renowned sport physician has warned Robert Kubica to skip Sunday's US grand prix. The Pole, limping only slightly, checked out of hospital on Monday following his frightening high-speed crash in Montreal just 24 hours earlier, vowing to be ready to race at Indianapolis. But Hamburg-based Dr Bernd Kabelka told Germany's Bild newspaper that Kubica risks death if he sustains another concussion at Indianapolis, which features concrete-lined banking that only a few years ago left Ralf Schumacher unconscious and in hospital.

"Sensory and motor losses are possible, so are memory gaps and visual disturbances," he said. "In the worst case the brain can swell and the pressure can be fatal. I consider it extremely dangerous for Kubica to drive again straight away." F1's former doctor Professor Sid Watkins, meanwhile, is also quoted as saying that the risk of serious injury with a second concussion is "quite high".

We can reveal, however, that Robert Kubica's name and helmet image is already featured atop the BMW-Sauber garage at Indianapolis, while both Sebastian Vettel and Timo Glock have travelled to the American city as possible stand-in pilots.

Team boss Mario Theissen said on Tuesday that F1's chief medical officer "will have the final say" when 22-year-old Kubica is examined at the circuit on Thursday.

He explained: "We are prepared in case Robert will not be able to drive. But, of course, we are all hoping that he will line up in the car at the weekend.

"The ideal scenario for me would be for us all to put the accident behind us quickly with a good performance in the race." (GMM)