Annie Power faces "eight to 10 weeks" on the sidelines with a possible stress fracture after being ruled out of the Hatton's Grace Hurdle at Fairyhouse.
The Willie Mullins-trained mare was declared for the Grade One contest on Friday morning but was subsequently found to be lame, although initial hopes were it could be a minor problem.
Mullins said: "It appears to be above the hock and she will go to Troytown for scans, so there will be no news until midweek at least.
"It's possibly a stress fracture and she'll be looking at eight to 10 weeks in her box."
Owned by Rich Ricci, the six-year-old lost her unbeaten record when second to More Of That in the Ladbrokes World Hurdle at Cheltenham in March, before bouncing back at Punchestown.
