John Smith's Grand National hope Backstage is injured and out for the season.
The 10-year-old, trained in County Meath by Gordon Elliott, was found to have heat in a tendon following a schooling session on Friday morning.
"He worked and schooled this morning and had a bit of heat in a leg," said Tim Palin, racing manager for co-owners Middleham Park.
"When he returned from exercise the vet came and found there was enough heat in there for it to be curtains for the season. We don't know at the minute whether it's 12 months out or if a summer out at grass will solve it."
Tenth behind Ballabriggs in last year's National, Backstage had enjoyed a highly successful campaign in point-to-points, winning all his six starts.
He was being prepared for a possible run at Cheltenham before having another crack at the Aintree showpiece in April.