Enable has lost her place as favourite for the Prix de l’Arc de Triomphe following news of a setback that will prevent her from racing for at least three months. The filly has a knee problem and connections are being understandably cautious about the prognosis but expect her to be fit for a pre-run in late summer before trying to win the Arc for a second time.

“Enable has met with a setback in training,” said a statement issued on behalf of her owner, Khalid Abdullah. “She has some filling in her knee which is being fully investigated. The advice we have is, that given reasonable circumstances, she should be ready to run in August as a preparation for the Prix de l’Arc de Triomphe.”

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It is a depressing turn of events for fans of Flat racing, the new season having officially begun only on Saturday. Enable was expected to be one of the stars of the summer, following her exploits last year, when her six consecutive victories included the Oaks, the Irish Oaks and the King George en route to her most recent success at Chantilly in October.

She was favourite to win the Arc on its return to its traditional home at the newly reopened Longchamp this autumn but has almost doubled in price to 5-1 since Monday morning. Her stablemate Cracksman has taken over at the top of the betting for the French race, with most firms offering no bigger than 11-4 about his chance.

Lord Grimthorpe, spokesman for Enable’s owner, said there had been no sign of a problem as recently as Friday, when the filly had impressed in “a swinging canter” on Newmarket’s gallops. “She had been doing fantastically well and we were looking forward to her beginning proper work this week,” he said in quotes first reported by the Racing Post.

“If it was a minor knock, we might be saying that, while she might not make the Coronation Cup [at Epsom next month], she could still be back later in June. But with this we are going to allow plenty of time for it to hopefully settle down and then aim to get her rolling in August.

“I don’t want to be nominating targets at this stage and that’s why I’ve simply said August for now. She’ll tell us long before that if she’s going to be ready or not, and we will keep everybody up to date when we know. Prince Khalid has had to deal with quite a lot of bad news over the years and he takes it stoically.”

If Enable were to follow the pattern she established last year, she would be seen next in the Yorkshire Oaks on 23 August and would not run between then and the Arc. In view of the late start she will make to this season, it would then be open to connections to take her to the Breeders’ Cup at Churchill Downs in November as a way of closing out what is likely to be her final year as a racehorse.

However, there must now be a distinct possibility that Enable has been seen on a racecourse for the final time, since Khalid Abdullah places great value on his hugely successful breeding programme and will be keen to see if she can produce other racers as good as herself. He will surely not countenance her return to action unless his vets can be sure the knee problem is resolved. With that factor doubtless in mind, Betfair punters allowed her to trade as big as 8-1 for the Arc on Monday.

Among those hoping for good news are her trainer, John Gosden, and her jockey, Frankie Dettori, though the Italian will at least be spared the agony of having to choose between her and Cracksman when Ascot’s King George comes round in late July. Dettori was effusive in his praise of Enable in October, when told she would be staying in training this year.

“To me she’s the filly of a lifetime,” he said at the time, “so of course I’m made up. What she’s done has been phenomenal. Everyone who likes racing wants to see her again.”