Coronation Cup winner Pyledriver has been removed from next week's Juddmonte International at York.
William Muir, who trains the high-class colt in partnership with Chris Grassick, had hoped his stable star would make the Knavesmire showpiece having already missed the King George at Ascot.
However, a muscle problem which appeared after he won the Coronation Cup at Epsom is taking longer to clear up than first hoped.
"We've run out of time, we were trying to get his groin right, (but) my physio she's very good and she said if I went and galloped I might put him back two weeks," Muir told Racing TV.
"You got to be 100 per cent. I wouldn't be going there gallop-fit, like I would have been going to the King George. We all had a chat and just made a decision - we'll go again and when he's 100 per cent he'll be there to fight.
"It's just frustrating as hell because you could drive upsides him, you can watch him trotting and he's trotting out like a lion, but if you push these soft tissue things just a bit too quick you might go backwards. I might get a mental problem with him and he might think he's always going to be sore.
"Years ago, when I first started out, I had Averti, and he pulled a muscle, and we just started to get back and we went a bit quick and then he did it again. It was pretty frustrating and it took me the next time before I got it right.
"When it came right he went on to do tremendous things, but you have to be patient and you can't win these Group One races unless you are 100 per cent. I'm not where I want to be so I've got to suck it and see.
"He's just been cantering away, quiet canters every day, and you drive upsides in the jeep when you think he's moving as well as you can ever say, but you can't see the little tear.
"The lads that look after him say to me 'boss, he's not quite right because he's very quiet, he's not biting us'. They're brilliant, they know him like the back of their hands so it's all little signs telling me 'just take your time with him until he's eating them again' and then away we go."