Champion Hurdle hope Grandouet is on Tuesday night undergoing surgery on his near-hind leg.
Owner Simon Munir confirmed the five-year-old was to be operated on for the injury that came to light over the weekend.
Grandouet, trained by Nicky Henderson, was to have had a prep run for next month's Stan James-sponsored race at Cheltenham in the Kingwell Hurdle at Wincanton on Saturday.
However, he was withdrawn from the race at the 24-hour final declaration stage after having banged his leg in his box on Thursday night.
Connections hope to know more on Wednesday about the horse's chances of still being able to take his chance in the Champion Hurdle.
Grandouet has been around an 8-1 chance for the feature on March 13 after staking his claim with victory in the International Hurdle at Cheltenham on his latest start in December.