Team Sky rider Ian Stannard is facing a prolonged period off the bike after breaking his back in a crash at Gent-Wevelgem on Sunday.
The 26-year-old Briton was catapulted off the road by touch of wheels with another rider 69km from the finish and came to rest at the bottom of a ditch.
He spent the night in hospital in Belgium and a CT scan confirmed he had fractured a vertebra.
Stannard is set to undergo an MRI scan in the UK later this week, when it should become clearer how long he will be out of action, but he is certain to miss both Sunday's Tour of Flanders and Paris-Roubaix a week later.
Team Sky doctor Phil Riley told teamsky.com: “Ian has a fracture in one of his vertebrae as a result of his fall. The fracture is stable and he will undergo a review with a UK-based neurosurgeon this week, as well as having an MR scan. That should allow us to find out more information following his CT scan on Sunday evening.”
The news is a major blow to both Stannard and Team Sky’s ambitions in the remaining spring Classics.
Stannard proved his strong form by winning Omloop Het Nieuwsblad earlier in March and had been expected to perform well at Paris-Roubaix in particular.
He said: "You can’t rush and injury like this and I have just got to rest up now. Once I have spoken to the specialist, I will have a better idea of what I can and can’t do, and then I will be able to focus on my recovery.
“I won’t know how long I’m out for until we speak to the specialist, but it’s not going to be in time for the Flanders or Roubaix.
“I’m gutted not to be riding in those races. To be honest, I haven’t had time to really think about it yet because it has been pretty painful 24 hours. They are only bike races at the end of the day, though. There are plenty more important things in life and there will be plenty more chances to ride them in the future.”
On how the accident happened, Stannard added: “Someone came across the road in front of me from the right and their rear derailleur got caught in my spokes. I thought I had got control of it, but then they looked around to see who they had hit and that flicked my bike again and I went straight into the ditch."
Stannard was not the only rider to have been seriously injured in an accident-strewn edition Gent-Wevelgem, with Lotto Belisol sprinter Andre Greipel suffering a dislocated his shoulder in a separate incident.