Aidan O’Brien has stated his intention to run River Tiber in the Prix Morny on Sunday – but warned the exciting colt suffered a setback in the lead-up to the race.

Last seen winning the Coventry Stakes at Royal Ascot, his third win from three outings, he is currently favourite for the Deauville Group One.

However, he missed a piece of work two weeks ago and O’Brien said it will be difficult to know how much fitness he lost as a result.

“The plan is to run River Tiber. He had a setback a couple of weeks ago so there will be a cloud over him when we do run him as we’re a bit worried about his fitness, but the plan at the moment is to run,” O’Brien told Sky Sports Racing.

“He had a hold-up and missed his second-last piece of work so he had that week off, but he did a piece of work this week so that gave him a chance to go.

“He seems to be in good form since, but the ground that we lost you couldn’t make back up with him.”

O’Brien also provided news of another of his stable stars who has been sidelined, last year’s Gold Cup winner Kyprios.

“Kyprios was at the Curragh for a canter last weekend after racing and that went well. He seems to have come out of that well,” said O’Brien.

“We’re looking at maybe starting at the (Irish) Leger, but that’s a tough enough race to come back in so we’d be hoping he could run a good race, come out of it OK and then have a look at something on Arc weekend, something like that, because you couldn’t expect him to perform at his best after such a traumatic year. If it all went well we could look at next year with him.”