Adayar will miss an intended comeback run in the Coronation Cup at Epsom's Cazoo Derby Festival early next month.
The 2021 Cazoo Derby hero went on to win the King George VI And Queen Elizabeth QIPCO Stakes at Ascot last summer before ending the campaign with a fourth in the Prix de l'Arc de Triomphe and fifth in the Champion Stakes over 10 furlongs back at Ascot.
Trainer Charlie Appleby was hoping to bring him back in the Group One over the Derby course and distance on Friday June 3, but has had to shelve plans as he won't have the horse fully fit in time after a hold-up.
"Adayar, who was an intended runner some months ago, has met with a minor setback and was coughing for a few days," said the Moulton Paddocks handler.
"I just eased off on him for a week and just in doing so he came on a lot in the week. We'll probably be giving the Coronation a miss, just fitness-wise I won't have him there in time.
"Adayar is most likely to be heading towards the Prince of Wales's [at Royal Ascot] for the first start of his four-year-old career."
Appleby will instead rely on Group Two winner Manobo, who was unbeaten in his first five starts before finishing second in the Dubai Gold Cup at Meydan on March 23.
"Manobo was last seen finishing second in the Dubai Gold Cup and we've always mooted that we wanted to drop him back to the mile-and-a-half," Appleby said.
"His preparation has gone very well towards the Coronation, we worked him this morning and he did very well. He is most definitely an intended runner in the Coronation."
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