Nicky Henderson-trained horse Altior is unlikely to run in the Queen Mother Champion Chase at this week's Cheltenham Festival after pulling up lame.
The news was confirmed by Henderson during the pre-Festival walk of the course, where he said that the 10-year-old was found to be lame on Sunday morning.
It now means that the showpiece event on Wednesday is unlikely to feature Altior in a three-way struggle with Defi Du Seuil and Chacun Pour Soi.
"We're working away and we'll either get lucky or we won't," said Henderson.
"It's due to an old splint that has been dormant. It's never bothered him before and, typically, it rears its ugly head now."
Henderson remains somewhat optimistic, and the four-time Festival winner is in as good hands as can be hoped.
"We’ve still got a chance. We’re using cold water on the leg, ice packs, the whole thing," said Henderson.
“I cannot put a percentage on it, that is the one thing I can’t do. We have just got to hope he comes sound in time.”
The problem appears to be either a split or a bony growth.
“He’s had the splint all his life but it’s never bothered him until this morning,” Henderson said.