Faugheen will not defend his Champion Hurdle title next month after being ruled out of the Cheltenham Festival due to injury.
The eight-year-old gelding was a well-fancied favourite to retain his crown on day one of the festival, but trainer Willie Mullins said the Irish raider is struggling with a ligament problem.
Mullins told the Racing Post on Wednesday: "Unfortunately, we've had a hold-up with Faugheen and he won't be going to Cheltenham.
"When we started back working him this week we discovered he had a sore suspensory and, while it isn't a serious problem, it's come at a bad time and it means we've had to abandon plans to run him in the Champion Hurdle.
"We were just bringing him back, we were only 28 days away yesterday, so I thought I best start doing a bit more with him. We did some serious work and afterwards he was just a little sore.
"The vet confirmed it was a suspensory. We just thought better to stop now and bring him back next year. The prognosis is very good.
"It's similar to what happened to Hurricane Fly going into Cheltenham and he came back and was as sound as a pound for five or six years, so we expect him to be as good as new next year."
Faugheen's jockey Ruby Walsh said: "It's very disappointing. It's like someone whipping the ace out of the pack, along with all the other cards."