Trainer Nicky Henderson says highly rated Altior is “extremely unlikely” to race in the King George VI Chase, the Boxing Day showpiece at Kempton Park.
After 19 successive wins, the nine-year-old lost by two-and-a-quarter lengths to Cyrname over two miles five furlongs at Ascot last month.
Henderson talked with jockey Nico de Boinville and owner Pat Pugh and agreed three miles at Kempton was a concern.
“He is not out, but it is unlikely. Nothing is certain in racing,” he said.
Henderson had better news at Cheltenham on Saturday as his 2-1 favourite Call Me Lord won the Unibet International Hurdle under James Bowen.
The six-year-old Call Me Lord had been thought to be better suited to right-handed tracks but had no trouble going left to take a leading trial for the Champion Hurdle in March.
Meanwhile, Warthog – ridden by David Noonan – got the better of Spiritofthegames to win the Caspian Caviar Gold Cup for trainer David Pipe.
Henderson had hoped to see an improvement in Altior, who has won the Queen Mother Champion Chase of around two miles for the last two years, during a training workout.
“It wasn’t as if he didn’t work well – it was very satisfactory as he worked with two very good horses. Nico just said he felt a little bit flat and he didn’t have his normal mojo,” Henderson added.
“He had a very hard race and was very tired after the race at Ascot. We don’t want to put him into another fierce battle as we might undo everything – the King George is extremely unlikely.
“What we do next, I don’t know. The King George is the one we really wanted to go for and I’m gutted about it.”
BBC racing correspondent Cornelius Lysaght
Just when one door closes, there’s nothing better than others springing open, and that could be the case with Nicky Henderson and the Champion Hurdle.
Although dual champion Buveur D’Air is out of this season’s big race because of injury, the trainer has as many as five ‘back-ups’, including Call Me Lord and fifth-placed Pentland Hills, about whose future prospects he went out of his way to talk up.
Call Me Lord saw off Ballyandy in a thrilling, scrambled finish, and represents the biggest success at jump racing’s HQ for his 18-year-old jockey James Bowen.