First Cornestone's bid for the Investec Derby is in the balance after the colt was ruled out of his Classic prep run at Leopardstown on Sunday.
The Team Valor-owned three-year-old, trained by Andrew Oliver, scoped badly on Saturday, causing him to miss the Derrinstown Stud Derby Trial.
Connections wanted to give last year's Group Two Futurity Stakes winner a run before aiming him at a race as important as the Derby and will see how the horse is before making plans.
"He scoped badly. We discovered it on Saturday. He worked very nicely on Tuesday and we were very happy with him, but he scoped badly yesterday and we checked again this morning to be sure," said County Tyrone-based Oliver.
"I've spoken with the owners and we just have to reappraise and see what our route is now. It is a huge disappointment.
"We were heading towards the Epsom Derby. It looks like he won't get a run prior to that so at this moment we have no firm plans. We just have to get the horse right again and find a race.
"It is unlikely he will run at Epsom because his preparation makes it less likely. He would need a run. It would be ambitious to head over to Epsom without a prep run.
"He was going for the Derrinstown and everything was going well. That's the nature of the game and we are going to reroute him.
"There is nothing set in stone. What's happened isn't serious, it's just unfortunate. We have to get him right, then finding a race of the quality we need and giving him sufficient time to recover for Epsom is going to be hard to do.
"He's in the King Edward VII at Royal Ascot and further down the line there's the Irish Derby and there's the French equivalent and he'd need a prep run before he went for that.
"We'll get the horse right and choose our route after that."