In-form trainer Willie Mullins is to rely on 50-1 shot Ballycasey for the chance of a second Grand National victory at Aintree.
Mullins has withdrawn his other two National entries - Prince De Beauchene and Boston Bob.
It means stable jockey Ruby Walsh, the only current rider to have won the race twice, could be on a big outsider in the race on 11 April.
"I am looking forward to running him there," said Mullins of Ballycasey.
Mullins, who saddled a record eight winners at the Cheltenham Festival earlier this month, added: "I think the spring ground will be better for him and his breeding suggests he will stay the trip."
The trainer and jockey teamed up 10 years ago to win with Hedgehunter. Walsh also triumphed in 2000 on Papillon for his trainer father Ted.
Retiring champion jockey AP McCoy will be riding in the National for a record 20th, and final time.
McCoy has yet to announce whether he will partner 8-1 favourite Shutthefrontdoor, trained by Jonjo O'Neill, or Gordon Elliott's 20-1 chance Cause Of Causes.
The 40-year-old Northern Irish rider has won once in 19 previous appearances - on Don't Push It for O'Neill in 2010.
"I am sorry for all the failures I have had in the Grand National over the years and this will be the last time I let anybody down but hopefully I will go out on a high and shut the front door behind me," he said.
|Grand National Odds|
|8-1 Shutthefrontdoor; 10-1 Rocky Creek; 12-1 Balthazar King, The Druids Nephew; 20-1 Cause Of Causes, Godsmejudge, Merry King, Spring Heeled, Unioniste; 25-1 Bar (Source: Betfred - Aintree's betting partner)|
The 74 remaining entries are headed by 2014 Cheltenham Gold Cup winner Lord Windermere, trained by Jim Culloty.
Eight-time champion trainer Paul Nicholls, who saddled Neptune Collonges to win in 2012, has six contenders.
Sam Twiston-Davies will ride Rocky Creek, Noel Fehily has been earmarked for Unioniste, while Nick Scholfield is set to team up with Sam Winner.
A rider has yet to be confirmed for Benvolio, while Ryan Mahon is set to be on recent Newbury winner Rebel Rebellion.
Sean Bowen, 17, is likely to be aboard Mon Parrain provided the teenager can qualify by riding one more winner.
Bowen is only three years older than one of the equine contenders - the 14-year-old Oscar Time, runner-up in 2011, will again be ridden by amateur jockey Sam Waley-Cohen.
A maximum of 40 runners will line up on the day, with the next stage for any withdrawals five days before the race.