Sakhee's Secret will not bid for back-to-back victories in next Friday's Darley July Cup at Newmarket.
The four-year-old failed to sparkle in his home-work after finishing last in the Golden Jubilee Stakes at Royal Ascot.
Trainer Hughie Morrison said: ‘I think he's a doubtful runner at the moment.
‘He ran too bad to be true the other day and though he is clinically fine, he had a temperature last weekend and I just think there was something simmering there.’
Morrison added: ‘You can't really take a chance with him in Group One company, if it was a handicap you might get away with it.
‘It's doubtful whether I'll confirm him tomorrow which is a shame, but that's life.
‘I think he's fine now but he appears to have had some sort of viral shock and we need to give nature a chance to let him fully recover and build up - even though outwardly you would think he was fine.
‘He was muscularly sore for the whole of last week.
‘It's a real sickener as the way he won the race last year, the stiff six furlongs there looks made for him.
‘The Nunthorpe and everything are possible at this stage.’
Duke of York Stakes winner Assertive is under consideration for the race.
Connections are prepared to forgive the five-year-old his latest effort when only 14th to Kingsgate Native in the Golden Jubilee Stakes.
At York he had previously beaten several of those who finished well in front of him in the Jubilee, including runner-up War Artist.
Richard Hannon jnr, son and assistant trainer, said: ‘There's a good chance he'll run in that race.
‘We do have a couple of other nice options for him, so it's just a question of weighing things up.
‘There wasn't really an excuse last time. He's a sprinter and they don't always run their race.
‘It happens, and he'll be back.’
Jeremy Noseda's Fleeting Spirit is also a confirmed absentee in the July Cup.
The Invincible Spirit filly was third in the King's Stand at Royal Ascot and is instead likely to be seen in the Coolmore Nunthorpe Stakes at York on August 22.
‘Fleeting Spirit is a non-runner in the July Cup, although she appears to be in good order,’ the Shalfleet handler said.
‘It has been decided, following a hard race at Royal Ascot when she was possibly not 100 per cent, that it would be unwise to ask her to compete at this level three and a half weeks later.
‘She will now be prepared for a tilt at the Nunthorpe.’
