Racing: Connections of Trabolgan feels it "very possible" the star chaser will miss the entire jumps season.
Nicky Henderson's eight-year-old suffered a tendon injury when clinically dismantling his rivals to win the Hennessy Cognac Gold Cup.
The Trevor Hemmings-owned gelding has not been seen on a racecourse since that triumph at Newbury last November.
Although hopes were this year high of Trabolgan's return to training, a latest scan confirmed the setback is taking longer than expected to heal.
"Unfortunately the healing process has been a slow one," said Hemmings' racing manager Michael Meagher, who is currently in the daily care of the horse.
"After the scan, our vet recommended the horse should not return to training just yet. Under the circumstances, it's very possible he'll miss this season.
"It's disappointing for everyone involved, including Mr Hemmings, but the horse will be given all the time he needs.
"The vet recommended the tendon should be rescanned at Christmas time," Meagher told the Racing Post. PA