Altior will not run in Wednesday's Champion Chase after being discovered lame on Sunday, according to trainer Nickey Henderson.
Henderson had admitted the 10-year-old would be lucky to line up as expected after struggling with a splint on his leg.
— PA Racing (@PAracing) March 10, 2020
It now means that the showpiece event on Wednesday will likely be a battle between the other two market principals, Defi Du Seuil and Chacun Pour Soi.
"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 said on Monday.
Altior was looking to win at an incredible fifth festival having won a Supreme Novices Hurdle, an Arkle Chase and the last two renewals of the Queen Mother Champion Chase.
Henderson had remained optimistic, but the four-time festival winner is now fully ruled out of the week's racing.
It will be a blow for Henderson and his team who is just one win behind Willie Mullins on the all-time list of Cheltenham festival winning trainers.
It compounds a frustrating season for Altior's connections. Their star chaser encountered a first defeat over fences at Ascot by Cyrname last November on his first race over a longer trip.
That prompted a rethink on the direction of his season and ruled out a King George bid. The dual champion chaser then missed the Clarence House before returning to the track an winning ways at Newbury in February.
That win looked to set Altior up nicely for a go at retaining his Champion Chaser crown, but that will not now happen. whta is next for Altior is pure speculation, but all going well a return to the Celebration Chase at Ascot in late April could be on the cards.