Irish trainer Willie Mullins says leading Grand National contender Prince De Beauchene is out of the big race on 6 April with a minor stress fracture.
"He will require at least six weeks' box rest so will miss the Aintree Grand National," said Mullins.
The horse was an 8-1 joint favourite alongside stablemate On His Own.
Beshabar has also been declared a non-runner by trainer Tim Vaughan because of a fetlock injury.
It is the second year running Prince De Beauchene has been a late withdrawal in the build-up to the race. He was ruled out with a hip fracture in March 2012.