White Moonstone has been forced to pull out of the 1,000 Guineas at Newmarket on 1 May.
Godolphin's unbeaten three-year-old filly pulled up stiff after her work on Saturday and has been scratched from the second Classic of the season.
White Moonstone, who won the Group One Fillies' Mile at Ascot in September when ridden by Frankie Dettori, is undergoing a veterinary investigation.
Saeed bin Suroor's inmate had been as low as 6-1 to secure Guineas glory.
Racing manager Simon Crisford told the Godolphin website: "Unfortunately, White Moonstone is not right and we need to find the cause of the problem.
"She definitely won't be able to run in the 1,000 Guineas."