Frankie Dettori will be sidelined for around three months after undergoing an operation on the ankle injury he sustained in a fall at Nottingham on Wednesday.

Dettori came off Eland Ally leaving the mounting yard before his race and was stood down for the rest of the day, having been in some distress.

Although an initial on-course prognosis suggested he had suffered only soft-tissue damage, X-rays subsequently revealed a fracture.

In a further development, Dettori's business manager Peter Burrell said the injury was even more serious.

"As well as fracturing his ankle, he has also broken his talus bone and he has had a plate and five screws inserted," Burrell said.

"Originally they were thinking he would be out for a couple of months, but now it is looking more like three months. The doctors think he'll need a month in plaster, a month in a boot and then it will be a month or six weeks for it to fully heal after that.

"Frankie has had masses of phone calls from people wishing him well and he is very grateful for that."

The injury could not have come at a worse time for Dettori as he had been due to ride one of the favourites, Treve, in Sunday's Prix de l'Arc de Triomphe.

It caps a miserable year for Dettori, who returned to the saddle on May 31 having served a six-month suspension after testing positive for a banned substance at Longchamp last year.

With the rest of this season out of the equation, Dettori will now have to look forward to 2014, when he has the prospect of riding some top-class horses for retained owner Sheikh Joaan Al Thani.

Burrell confirmed Dettori still hoped to be back to ride at the Dubai Carnival at Meydan, which commences in early January.