Inglis Drever became the latest high-profile casualty of the New Year when he was ruled out for the rest of the season with a tendon injury.
Three leading Cheltenham Festival candidates have now been sidelined in as many days, with Harchibald and Kicking King also suffering setbacks.
Inglis Drever, trained by Howard Johnson, was on course to defend his Ladbrokes World Hurdle crown but is now unlikely to be seen out before Christmas.
The seven-year-old scored at Wetherby on his seasonal bow and then landed the Ballymore Properties Long Distance Hurdle at Newbury in November.
It is thought he picked up the injury around the time of his second run and that may account for his fall when already looking beaten in the totesport Long Walk Hurdle at Chepstow.
''He has had a lot of hard races and we think the problem might have surfaced after the Newbury race,'' said owner Graham Wylie.
''That would explain why he wasn't travelling very well in the Chepstow race and that run could have aggravated it even more.
''He seemed fine at the weekend apart from a little bit of swelling on his leg, which we thought was nothing more than bruising and it would go down.
''We had him scanned this morning and there is a hole in his tendon, so we will have to get him sorted out.
''If we had ignored it and carried on it might have made it worse, so we have done what is best for the horse.''
Wylie's No Refuge had already been prominent in the betting for the Cheltenham stayers' contest and the Royal & SunAlliance Hurdle winner will now take over the mantle from his stablemate.
''No Refuge would have to come into the picture now,'' added Wylie. ''We have always wanted to try him at three miles and he was always there in case something happened to Drever so we'll see how he goes.''
Crook-based Johnson said: ''He had that fall at Chepstow and he was sound enough when he came home, but he had been lame at the track.
''We nursed him for a week and he did a little bit of swimming. Yesterday I gave him a walk out and a jog and I just wasn't 100 per cent happy, so I called the vet in.
''He scanned him and behind the knee there is a black hole, which tells you enough is enough for the season.
''We weren't forced to run him at Chepstow, but I thought we would get another run into him before Cheltenham and I was going to run No Refuge, but he had a stone bruise and didn't run.
''We thought Drever was fit enough just to take the race in his stride and it has happened like this - but that is racing."
''He won't be ridden out again this season. We have to decide whether he has to be fired or just left for mother nature.
''No Refuge worked this morning and looked great and Royal Rosa is on the way back, but he has to have soft ground.
''They are my two three-milers waiting in the wings and we will have to put them in the races where Drever was going to go.''
Johnson's charge lowered Baracouda's colours at Cheltenham last March and handed out another beating in the Newbury race.
The Francois Doumen-trained runner is now the 4-1 co-favourite with Coral alongside No Refuge and Rhinestone Cowboy.
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