Godolphin have been forced to call a halt on the career of Australian import Denman as he will not be fit enough to do himself justice in next week's Darley July Cup.
The four-year-old, not to be confused with his National Hunt namesake, will now take up stud duties Down Under, which was always the plan for the son of Lonhro.
Connections had hoped to run him in the highlight of the July meeting at Newmarket but have run out of time.
Godolphin racing manager Simon Crisford said: "We are not going to run him in the July Cup because he is not fit enough.
"What the plan is, and what the plan has always been, is that there is a quarantine for Australia straight after the July meeting, and the intention was that he would always return to the southern hemisphere and we don't have time to find another race for him.
"Quarantine starts straight after the July meeting and he's not ready to run so unfortunately we've run out of time.
"It was always going to be 50-50 whether we could get him ready in time and he wouldn't be ready to do himself justice, so he's going to start quarantine and go back to Australia."
His impending withdrawal would free up Frankie Dettori for the ride on Fleeting Spirit if that is the direction in which her trainer, Jeremy Noseda, decided to go, with Tom Queally, who partnered her to victory 12 months ago, also in the frame.
Another who will miss the race is Brian Meehan's Arcano.
One of last season's leading juveniles, the colt has only been seen once this season, when well beaten by the Richard Hannon pair of Dick Turpin and Canford Cliffs in the Greenham Stakes at Newbury.
He had still been quoted by bookmakers for the sprint on the July Course but connections admitted it will come too soon.
"Arcano is on his way back," said Angus Gold, owner Sheikh Hamdan Al Maktoum's racing manager.
"His blood took a long time to get back right after Newbury, it was just a few silly little things that have taken him a bit longer than we hoped.
"We were hoping to get him ready for the July Cup next week but he's not quite going to make it.
"I hope he will be back on the track in the next two to three weeks."
A decision on Marchand D'Or's participation has still to be reached.
The seven-year-old won the Group One two years ago when in the care of Freddie Head, but is now trained by Mikel Delzangles.
He came back to form with a Group Three win at Longchamp in May but could only finish 11th behind Starspangledbanner in the Golden Jubilee Stakes at Royal Ascot last month.
"Everything is OK with him, but we are still not sure whether he is going to go to Newmarket for the July Cup or not yet," said Delzangles.
"His options are Newmarket or the Prix De Ris-Orangis at Maisons-Laffitte (July 17) the week after.
"He's won the race before at Newmarket so that is in his favour, but it might be a bit tough to ask him to run there after Ascot again.
"He seems to be OK, though, so we'll decide at the beginning of next week."