Kingman colt Calyx was one of the favourites to win the Commonwealth Cup in Berkshire this month after racking up three consecutive victories at Newmarket and Ascot twice.
However, the three-year-old suffered a shock defeat when finishing second at Haydock Park last time out and Grimthorpe has now confirmed the John Gosden-trained charge has been ruled out of the Royal meeting.
He was quoted as saying by The Irish Field: ‘Following his run in the Sandy Lane Stakes, it has been revealed that Calyx sustained a pastern injury which is now being investigated.
‘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.’
Antonia De Vega kept her Classic dreams alive after she ran out an impressive winner of the Johnnie Lewis Memorial EBF Stakes at Newbury.