Sir Mark Prescott's lightly-raced four-year-old is 7/1 ante-post favourite with Sky Bet for the mile-and-three-quarters feature on the back of a fine third in the Northumberland Plate on what was only his fifth career start.
"It's not looking good. The forecast is for no rain really. It all depends on the weather," said Tim Palin, partner and racing director for owners Middleham Park, Mrs Jones and Osborne House.
"The horse is in great shape. I saw him on the treadmill on Saturday and saw him swim as well. The horse is in A1 nick, but we believe he wants cut in the ground. Unless we get the rain, he'll be a non-runner unfortunately.
"If there is rain forecast, we will declare him. If there isn't, we probably won't even declare him. We might have to make the harsh decision of taking him out.
"It would be a shame as obviously he's got a first-rate chance."
Jedd O'Keeffe also has ground concerns for 33/1 chance Lord Yeats. The North Yorkshire handler is keen to run the four-year-old in Europe's richest handicap as long as conditions are suitable.
"The horse is in great shape. I'm really happy with him. It's the weather we're watching closely," he said.
"Ideally we'd like plenty of give in the ground. I can see a bit there maybe on Wednesday. Whether they will get enough, I don't know, but the intention is to go if the surface is safe for him."
A total of 72 horses stood their ground at the five-day confirmation stage but only the top 20 in the handicap can run.
Listed winner Lord Yeats is guaranteed a place as is the Mark Johnston-trained Soldier In Action (16/1), who won a big handicap at Glorious Goodwood on his latest start.
"Alan and Michael (Spence, owners) were both keen to run here after he won at Goodwood and he seems in good form," said Johnston's son and assistant, Charlie.
The weights are headed by William Haggas's Dal Harraild while two Irish-trained horses towards the top of the handicap are Aidan O'Brien's US Army Ranger and Ivan Grozny, from Willie Mullins' stable.
Others in the mix include Scarlet Dragon, Elidor, Mount Logan, Montaly, Top Tug and Dubka.
