Leading contender Unioniste is first reserve for the Paul Stewart IronSpine Charity Challenge Gold Cup at Cheltenham on Saturday.
The Paul Nicholls-trained four-year-old has been disputing favouritism with some bookmakers for the prestigious handicap having run so well in novice company when third behind Dynaste at Prestbury Park a month ago.
Connections now face an anxious wait to find out whether he will get a run and that could hinge on whether Doncaster's meeting on Saturday gets the go-ahead.
The Ferdy Murphy-trained duo of Divers and De Boitron have both been declared with the race as their second preference.
Murphy said: "The plan is for both of ours to go to Doncaster if the meeting goes ahead. Divers is going to run in the two-mile-three-furlong race there and De Boitron goes for the three miler.
"But it was no more money for us to declare for Cheltenham as a second preference so with the way the weather is, it was a no-brainer."
The course at Doncaster is currently frozen, but temperatures are due to rise from Friday morning.
However at least one of the Murphy-trained pair would need to be formally withdrawn by 9am on Friday for Unioniste to be allowed to take their place in the final line-up.
Harry Derham will take the ride on Unioniste if he does line up, with his 5lb claim a big help considering he runs from 6lb out of the handicap.
"He's got his weight because he's got a rating of 137, but he gets a 7lb allowance as a four-year-old," said Nicholls.
"Hopefully he will get in because with Harry taking off 5lb he's got a nice-looking racing weight of 9-9."
Ruby Walsh partners stablemate Cristal Bonus, a hugely-impressive winner on his seasonal reappearance at Down Royal.
"Every bit of rain that arrives on Friday will help his chances, because he loves soft ground," added Nicholls.
A total of 18 horses including Unioniste were declared, but Hunt Ball was a notable absentee.
The seven-year-old was one of the major success stories of last season after seven wins catapulted him and his owner Anthony Knott to stardom.
However, he was pulled up on his return in the Paddy Power Gold Cup, with connections blaming the testing ground, and trainer Kieran Burke said that he felt conditions would again be unsuitable this weekend.
Burke said: "We've decided not to run him. It's purely because of the ground and I think they're forecast more rain yet.
"There's no point running him on soft ground as he showed in the Paddy Power he just doesn't handle it at all.
"He's in very good order and the plan is to go straight to Kempton now for the King George on Boxing Day."
Alan King's Walkon is clear market leader with most bookmakers following his excellent second in the Paddy Power.
Philip Hobbs had Menorah and Wishfull Thinking engaged at the confirmation stage, but only the latter has been declared.
He snapped a long losing run at the track last month and carries top-weight of 11st 12lb on Saturday.
Nicky Henderson saddles both Quantitativeeasing and Nadiya De La Vega, ridden by Barry Geraghty and Tony McCoy respectively.
Other leading contenders include David Pipe's Notus De La Tour and Astracad from the local stable of Nigel Twiston-Davies.
The Naunton handler could also be represented by Have You Seen Me who has been off the track since finishing second over the course and distance in a novices' handicap chase at Cheltenham in April, 2011.
He will be ridden by Adam Wedge and Twiston-Davies said: "Have You Seen Me is down there at the bottom of the weights and he is also in good form. It is his first run for a while but hopefully I have him fit enough and he should run a good race."
However, it is Astracad, who won the Jenny Mould Memorial Handicap Chase at The International last year, that leads the stable's attack.
The six-year-old continued his good record around Cheltenham when finishing fourth in the paddypower.com Handicap Chase over two miles at The Open on his seasonal debut in November.
Twiston-Davies said: "Astracad has been in brilliant form since his run at The Open and I think he has come on a bit for that run.
"The extra half mile in the Paul Stewart IronSpine Charity Challenge Gold Cup will definitely help him and I don't think soft ground will be a problem either."