Aidan O'Brien could rely on either Kingsbarns or Ruler Of The World in Saturday's Champion Stakes at Ascot after admitting to fears about ground conditions for both Declaration Of War and Magician.

The Ballydoyle handler left the quartet of runners in this weekend's 10-furlong Group One at Monday's confirmation stage, with Kingsbarns, Declaration Of War and Magician also among the entries for the Queen Elizabeth II Stakes on the same card.

However, with ground conditions at Ascot looking certain to be on the easy side, Declaration Of War could be saved for a trip to the Breeders' Cup meeting in California next month.

Irish 2,000 Guineas winner Magician, not seen since finishing last in the St James's Palace Stakes at Royal Ascot, also looks likely to miss Champions Day.

Speaking at Limerick on Monday afternoon, O'Brien told At The Races: "Declaration Of War could maybe struggle to run, because if the ground is not good or better he won't run.

"If he doesn't run, he'll probably go straight to the (Breeders' Cup) Classic.

"Magician is a little bit the same, he wants real good ground as well.

"Ruler Of The World and Kingsbarns are in and both of those have form with ease in the ground, so maybe they'll run if the rain keeps coming as it is.

"He's (Kingsbarns) in the Queen Elizabeth and he's in the Champion and Ruler Of The World is only in the Champion.

"Whether the two of them will run in one or they'll split up, I'm not sure."