Still not sure why, WEG panel found them unfit to drive, which is a fitness thing, not medical or lameness.

U.S. driver David Saunders had to withdraw Wednesday from the combined driving competition after two of his five Morgan horses failed to pass the pre-competition vet inspection.

Because two horses were ruled out by the ground jury, Saunders, who was competing as an individual, did not have the necessary number for a four-in-hand team.

U.S. chef d'equipe, or team manager, Ed Young said afterward the inspection results were a shock because U.S. team vets had deemed the horses fit.

"Very disappointing," Young said. "It was a complete surprise to us. We were baffled."