Nicky Henderson will do all he can to get Altior to the Champion Chase after revealing the brilliant two-miler was found to be lame yesterday.
Altior suffered his first career defeat over jumps at Ascot in November, but bounced back on his return to his favoured two miles in the Game Spirit at Newbury last month.
All had been set fair for an eagerly-awaited showdown with Defi Du Seuil and Chacun Pour Soi at Cheltenham on Wednesday. But Henderson revealed yesterday: "Unfortunately Altior was lame this morning, due to an old splint that has been dormant.
"It's never bothered him before and typically it rears its ugly head now.
"We are working away and there's lots we can do, we have two days, but it's an uphill battle. We have the treadmill he can go on and it's very cold water, which helps these things a lot.
"We're working away and we'll either get lucky or we won't. He was sound as a pound yesterday - you wouldn't have seen a sounder horse."
Elsewhere, Gordon Elliott has confirmed that many people's Irish banker Envoi Allen will run in Wednesday's Ballymore Novices' Hurdle.
During the week, Elliott floated the "possibility" that his unbeaten novice could switch to the Supreme Novices'.
However, the Cullentra handler walked the course yesterday morning and is happy for his charge to sidestep tomorrow's curtain-raiser.
Speaking on Racing TV's Luck on Sunday programme, Elliott said: "We walked the track at 7am... I think it will be beautiful ground on Tuesday and Wednesday, hopefully, so we're going to go with our original plan."