John Gosden's star sprinter Calyx has been ruled out of the Commonwealth Cup at Royal Ascot through injury.
After a first career defeat in the Sandy Lane Stakes at Haydock last month, it emerged after the race that he picked up a pastern problem.
The pastern region in a horse is particularly vulnerable to the effects of direct trauma, such as a penetrating injury, due to its closeness to the ground and lack of protection.
It has important anatomical structures close under the skin, which are exposed to penetrating injuries, whilst tendon and ligament structures on the back of the pasture are also liable to strains.
Teddy Grimthorpe, racing manager for owner Prince Khalid Abdullah, said in a statement: "Following his run in the Sandy Lane Stakes, it has been revealed that Calyx sustained a pastern injury which is now being fully investigated by the team.
"This will rule him out of the Commonwealth Cup at Royal Ascot, but we are hopeful that he could run again in the latter half of the season."
Despite being just three years old, Calyx has previous history of seasonal ending injuries.
After winning the Coventry Stakes as a juvenile last term at the Royal meeting, he was not seen again until his impressive return at Ascot on the first of May in a Commonwealth Cup trial, having chosen to sidestep the Guineas.
Connections are hopeful the speedy son of Kingman can be seen again this season, with somewhere in the Autumn his likely return date.
His exclusion of the Group One three-year-old Champion sprint over six furlongs allows Aidan O'Brien's Ten Sovereigns to soak up an unchallenged role of favouritism.
The Ballydoyle colt could not see out the mile trip in the Guineas having been prominent early on under Ryan Moore, and faded back to fifth after stablemate Magna Grecia took the Classic honours.
He was however three from three as a juvenile over six furlongs, and a return to the sprinting division is very much required.
Calyx's successor in the Sandy Lane - Hello Youmzain sits next best for Kevin Ryan.
Simon Crisford could send the Hamdan Al Maktoum owned Jash to the royal meeting, as the owner seeks to follow up last year's success with Eqtidaar.
Jash was another high-profile individual that opted to skip the Guineas, and made his season appearance when winning the Listed King Charles II Stakes over seven.
Lady Kaya ran a blinder in the 1,000 Guineas for Sheila Lavery, and is certainly the filly of interest again down in trip.