Leading Grand National fancy Inn At The Top is set to miss the race.
Jim Turner's charge was as low as 14/1 for the Aintree showpiece.
But Turner will not risk the horse after heavy rain made the ground testing.
"It's very unlikely he'll run. Obviously I'll have to let Weatherbys know this morning," said Turner.
"I've had a word with the owners and they said I can do whatever I think is right.
"If it's going to be really hock deep it's pointless running him.
"It's sickening for the all the stable and everybody.
"I had a word with his jockey Adie (Smith) last night and he's fed up as well. There's nothing we can do."
Inn At The Top's withdrawal will allow the Irish-trained Merry People, the first of four reserves, to take his place in the £500,000 spectacular.
Turner is now eyeing the Whitbread Gold Cup at Sandown in three weeks' time for the nine-year-old.
"The Whitbread will be the next one," he added.
And he is hoping the weather at Aintree will be kinder next year to give Inn At The Top the chance to run in the National.
"I hope we can come back next year," he added.
Ironically, conditions at Aintree have improved slightly following a dry night, but rain is forecast later today.
Clerk of the course Ian Renton said: "At the moment conditions are a little bit improved.
"We had a dry night but the bad news is there is more rain forecast today - not as much rain as yesterday. We are though talking about definite rain from probably in the not too distant future through the afternoon."
The going is soft on the Grand National course and soft, good to soft in places on the Mildmay and Hurdle courses