Ten Sovereigns, the Middle Park Stakes winner, has been ruled out of the Darley Dewhurst Stakes at Newmarket on Saturday.
Connections had been considering stepping the unbeaten colt up to seven furlongs for the first time at the weekend but trainer Aidan O'Brien said on Wednesday: "We thought about running him but he had three runs in a relatively short space of time [five weeks] and, in fairness to the horse, we've decided to leave him alone until next season."
O'Brien will be represented by Anthony Van Dyck, winner of the Group 2 Futurity Stakes at the Curragh in August and runner-up to Quorto in the Group 1 National Stakes last month, Christmas, runner-up in the Futurity and third in the National Stakes, and possibly Royal Lodge Stakes winner Mohawk.
While a final decision about William Hill St Leger third Southern France's participation in the Dubai £500,000 Cesarewitch on Saturday will be delayed until Thursday morning, the son of Galileo looks set to take his chance.
O'Brien added: "It will be a big ask for a three-year-old but he'll have nice ground and we'll learn more about him with next year in mind. He stays well and is in good form."