Britain's four-time Tour de France winner Chris Froome was taken to hospital and will miss the rest of the Criterium du Dauphine after crashing before stage four.
The incident took place during what Team Ineos described as a "recon" of Wednesday's 26.1km time-trial course in Roanne, France.
Froome, 34, was eighth overall after three stages of the eight-day race.
He was using it as part of his build-up to the Tour, which starts on 6 July.
Team Ineos said they would "provide a further update in due course".
Froome is planning to win a record-equalling fifth Tour win, with three of his successes in the race coming after victory in the week-long Dauphine.
The six-time Grand Tour winner recently completed a second training stint in Tenerife in readiness for the Dauphine, his fifth race of the year.