Double Seven, who finished third when joint favourite in the 2014 Grand National for champion jockey AP McCoy, has been ruled out for the season.
Trainer Martin Brassil said the horse, an early favourite at 25-1 for this year's 11 April race, had a setback.
"He's out for the season, unfortunately," Brassil said of the nine-year-old, owned by JP McManus.
"We're very hopeful that we'll be able to get him back next season and go back to Aintree again, though."
Brassil, based in County Kildare, won the 2006 National at Aintree with Numbersixvalverde, ridden by Niall 'Slippers' Madden.