A knee ligament injury will force Annie Power out of Cheltenham and probably the remainder of the season, in what Willie Mullins has described as a "huge blow for the season".
Perhaps the most popular mare in training, she could have defended her Stan James Champion Hurdle title in March or reverted to the OLBG Mares' Hurdle, the race in which she fell when set to win in 2015.
Mullins reported on Tuesday at lunch time that Annie Power was in excellent shape. Later that evening, an issue came to light and the injury was since confirmed.
He said: "Normally when a horse gets an injury like that we give them a week or 10 days and then reassess and I think that's what we'll do. She's going to be a huge loss to us this season."
The blow is cushioned somewhat by the return to form of Faugheen, which has also not run this term. He will reappear in Sunday's BHP Insurance Irish Champion Hurdle.
"Faugheen worked yesterday and will run. I'm hoping for a big run.
"He has the rating for the race, but is going to meet race-fit horses. He's run on good ground in Cheltenham and Punchestown, so I don't think that's a problem, and there is some rain forecast before Sunday."
Faugheen is now a best-priced 13/8 for the Cheltenham Champion Hurdle. Annie Power's absence from the Mares' Hurdle betting sees stable ally Vroum Vroum Mag heads the betting at 7/4. Apple's Jade is next best at 2/1, and Limini is 4s from 7/1.
Un De Sceaux is on course to run in the rescheduled Clarence House Chase on Saturday, while Vroum Vroum Mag is bound for the olbg.com Doncaster Mares' Hurdle on the same afternoon.
"Un De Sceaux goes for the Clarence House in Cheltenham and Alelchi Inois goes for the cross-country," said Mullins. "Vroum Vroum Mag is likely to go to Doncaster."