Coneygree, last season's Cheltenham Gold Cup winner, has been ruled out with injury for the rest of this campaign.
The eight-year-old, who looked so impressive on his return to action at Sandown in November, had been in the frame to run over Christmas in either the King George VI Chase at Kempton or in the Lexus Chase at Leopardstown.
But trainer Mark Bradstock's plans have been derailed after his stable star suffered what is believed to be slab fractures in both hocks.
The injury is not thought to be career-threatening, but time has been called on a season which would have culminated in a second bid for the Gold Cup at Cheltenham in March.
