Fernando Alonso may be heading into surgery on Friday to repair a potentially broken jaw and teeth.
Alpine has confirmed alarming reports that the 39-year-old Spaniard was struck by a car on Thursday whilst road cycling near his home in Switzerland.
With the season opening Bahrain GP looming in March, the Enstone based team said Alonso is "conscious and well in himself" and will undergo further tests on Friday morning.
Italy's La Gazzetta dello Sport says the two-time world champion never lost consciousness but may need surgery for a jaw fracture and tooth damage.
He will reportedly be transferred to a specialist hospital in Bern for the operation.
The Spanish sports daily Marca said doctors are optimistic that Alonso, whose injuries are reportedly "not serious", will be well enough for the start of official testing mid next month.
"If there is a mandibular fracture, the tests will be because they want to see if there is a displacement and whether to put a plate on it," a medical specialist, Dr Jose Gonzalez, is quoted by Spain's AS newspaper.
"If it really is a clean fracture, there should be no need for further testing. Either way, whatever it is, it is not a major injury.
"It can be said, with almost complete certainty, that he will be at the pre-season tests in Bahrain without any problems," Dr Gonzalez added.