Reigning favourite Forgotten Rules remains in contention for the Gold Cup at Ascot but injury will keep Brown Panther out of the race.
Trainer Dermot Weld wants softer ground on Thursday for Forgotten Rules but Ascot has so far escaped the rain that has hit many parts of the country.
"As has been well documented, the ground is vital," Weld said.
"Unfortunately Ascot missed all the thunderstorms, but we're very hopeful.
"If the ground is safe he'll run. He's a very high-class horse."
The globe-trotting Brown Panther, eighth in the 2013 Melbourne Cup, was ruled out on Saturday after suffering a setback.
The Tom Dascombe-trained seven-year-old passed the post a close fourth in last Gold Cup before before going on to claim Group One glory in the Irish St Leger at the Curragh.
"He suffered an injury this morning and he needs some anti-inflammatories, so he won't be able to run on Thursday," Dascombe said.
"At this stage we don't know the extent of the injury."