Crystal Ocean suffered a career-ending injury on the Newmarket gallops on Thursday morning.
The Sir Michael Stoute-trained five-year-old was taking part in a routine canter as his preparation for either the Prix de l’Arc de Triomphe or the Champion Stakes at Ascot continued.
While it is hoped the Sea The Stars entire will recover to enjoy a second career at stud, his racing days are over.
Peter Stanley, spokesman for owner Sir Evelyn de Rothschild, said: “He’s had to have two screws inserted into a cannon bone.
“He’s fine after surgery, he’s come through the operation and is up and about.
“At this stage the vet sees no problem at all in him heading to stud, but it is early days.
“Obviously it didn’t happen long ago, but the hope is that he makes a full recovery.”
Never out of the first three in a 17-race career, Crystal Ocean was involved in an epic battle for this year’s King George VI And Queen Elizabeth Stakes at Ascot, just losing out to Enable.
For a brief spell he was the highest-rated horse in the world and finally landed the Group One his consistent efforts deserved at Royal Ascot in the Prince of Wales’s Stakes, where he was ridden by Frankie Dettori.