"We will also have Black Sam Bellamy, Sorcerous and Sholokhov staying in training as a four-year-olds and Milan also stays in training."
It marks a change in direction at Ballydoyle, where O'Brien's trainees ordinarily race exclusively at age two and three and are either retired to stand at Coolmore or sold.
Black Sam Bellamy is a full-brother to Galileo who won the Group I Gran Premio del Jockey Club at San Siro in Milan in October. Sholokhov, often used as a pacemaker, was second in both the Group I Irish Derby and the Eclipse.
Sorcerous was unable to achieve the high hopes his connections had for him at three, when he was considered a Derby hope, while Milan was injured in May and has not raced since.