The Cheltenham Festival Bumper joint favourite, Youlneverwalkalone, is likely to miss the race.
The JP McManus-owned, Christy Roche-trained gelding finished "stiff and sore" after working yesterday morning and Roche described him as "an unlikely runner".
Roche added: "We thought it was a muscle problem but now we are not so sure. If he is not 100 per cent then we will not risk him. We will know more in the next three or four days but at this stage I would say he is an unlikely runner. It's very disappointing."
Youlneverwalkalone shot to the head of the Festival Bumper market after winning his only start to date at Leopardstown over Christmas. Sean Graham bookmakers made him 6 to 1 joint favourite for Cheltenham with Golden Alpha.
Roche, however, could still have as many as five runners at Cheltenham including the former top juvenile hurdler, Grimes, who could have his first start over fences in the Arkle Trophy.
"He is a possible if the ground dries out. We are unlikely to get a run into him now because of the ground but we will look at the situation nearer the time. The horse is in good form and he is pleasing us," said the Curragh trainer. Significantly, Grimes is as low as 14 to 1 for the Arkle after being backed down from 33 to 1 in recent weeks.
Roche again dismissed previous rumours about the well being of his star novice, Joe Mac, who remains at the head of the Citroen Supreme Novices' Hurdle market. "He has always been in good form and we are very happy with him," he said.
Afarad is still on target for the Triumph Hurdle, Shannon Gale could take part in one of the handicap hurdles and a surprise runner may be King Wah Glory, who has not run since October 1997. "King Wah Glory has four entries and will go for one of the chases," Roche said.
Meanwhile, Paul Carberry expects to return to race riding within 10 days, well before the Cheltenham festival.
Initial fears that the top jockey had broken his collarbone in a fall from Wyatt at Navan on Sunday were disproved when X-rays showed Carberry had sustained shoulder and rib injuries.
"My shoulder is pretty badly bruised and I've cracked a couple of ribs. I'm feeling a little bit sore but it's not too bad. I'll be back in 10 days, which is a relief," Carberry said yesterday.
"I'm not sure what happened but I think the horse coming after us kicked me. It always seems to be the way," Carberry added.
Nobody was more relieved by the news than Wyatt's trainer Noel Meade, who faces another anxious wait on the results of tests taken on his big Cheltenham hope, Cardinal Hill.
"We are waiting on a few blood test results on the horse. We hope to know more on Wednesday," Meade said yesterday. One horse who will now go straight to Cheltenham is the former champion chaser, Klairon Davis, who will not have a warmup race at Naas on Saturday.
This year's Queen Mother Champion Chase will be Klairon Davis's fifth consecutive appearance at Cheltenham. The French-bred won the Arkle Trophy in 1995 and the Champion Chase in 1996. Another former festival winner will also go straight to Cheltenham. Wither Or Which, the 1996 festival bumper winner, has been confirmed a definite runner in the Citroen Supreme Novices Hurdle.
