Cairo Prince has sustained an ankle injury that will rule him out of the May 3 Kentucky Derby, Daily Racing Form's David Grening reported via Twitter.

Trainer Kiaran McLaughlin told Grening that Cairo Prince injured his left front ankle, and the colt is bound for Rood and Riddle Equine Hospital near Lexington, Kentucky, for "further evaluation."

Cairo Prince was listed 19th on the Derby list with 24 points to his credit. His defection now allows another Pioneerof the Nile colt, Vinceremos, to move up into the Derby field at number 20.

In another significant ramification, Cairo Prince's rider, Luis Saez, will now jump back on Wildcat Red. That colt's trainer, Jose Garoffalo, had been hoping to get Saez, since he had guided Wildcat Red to a hard-fought decision in the Fountain of Youth. When Saez was committed to Cairo Prince, Garoffalo lined up Rafael Bejarano for the Derby mount. But the Southern California-based rider has been replaced, now that Saez has become available.

Victorious in last fall's Nashua in his stakes debut, Cairo Prince missed by a nostril to Honor Code, who has likewise been sidelined by injury, in the November 30 Remsen. He kicked off his three-year-old campaign with a 5 3/4-length romp in the January 25 Holy Bull, prompting McLaughlin to describe him as his best-ever hope for the Kentucky Derby.

Darley subsequently purchased a majority share in the exciting prospect from his ownership group of Namcook Stables, Paul Braverman, Harvey A. Clarke and W. Craig Robertson III.

Opting to skip the February 22 Fountain of Youth, Cairo Prince trained up to the March 29 Florida Derby. He made his debut in the Godolphin colors in that Gulfstream Park feature, only to wind up a flat fourth as the 6-5 favorite. His subpar effort briefly jeopardized his chances of making the Kentucky Derby field, but thanks to a few defections, his 24-point total turned out to be sufficient.

Cairo Prince worked once since the Florida Derby, breezing a half-mile at Palm Meadows in :48 3/5 last Sunday.