Legal Right will miss tomorrow's Jim Ford Challenge Cup Chase at Wincanton tomorrow after suffering a "little setback".
The seven-year-old has had a history of problems but has managed to win three races this season, including the Tripleprint Gold Cup at Cheltenham in December.
Trainer Jonjo O'Neill - who had booked Tony McCoy to ride his stable-star tomorrow - did not know if the problem would stop the gelding running at next month's Festival.
He said: "He's had a little setback. We don't know what it is yet - we'll just have to wait and see what the vet says.
"He's had a load of problems and this is just another to add to the list.
"It is very frustrating but we've been there before and we'll be there again."
A field of five horses has been declared for tomorrow's £25,000-added contest.
They include the Alan King-trained Tote Cheltenham Gold Cup entries Mulligan and Spendid, who both had alternative engagements in the Racing Post Chase at Kempton.
Paul Nicholls also has two runners, Escartefigue, who holds a Gold Cup entry, and the novice Arlas. The Ron Hodges-trained Melling makes up the field.
No winner of the Jim Ford Chase has gone on to lift the Gold Cup in recent years.
But Master Smudge, a faller in 1980, was awarded the race at Cheltenham on the technical disqualification of Tied Cottage and the 1998 Wincanton second Strong Promise went on to fill the same position in the Gold Cup.
By contrast, both Kribensis in 1990 and Alderbrook in 1995 used the Kingwell Hurdle as a stepping-stone to victory in the Champion Hurdle.
And I'm Supposin followed his victory here two years ago by finishing third at Cheltenham.
However, the Francois Doumen-trained Hors La Loi III, winner of the Citroen Supreme Novices' Hurdle at Cheltenham last year, is the only one of the four runners in this year's renewal with a Champion Hurdle entry.
