Betfred Cheltenham Gold Cup hero Synchronised is one of 59 that remain in the John Smith's Grand National after Tuesday's scratchings stage.
Jonjo O'Neill's charge is rated 8/1 favourite to become the first horse since Golden Miller in 1934 to win chasing's two biggest prizes in the same season.
"He's been left in but we'll wait until nearer the time before we make any decisions," said Frank Berry, racing manager for owner JP McManus.
"He was tired for a day or two after Cheltenham, which you would expect as it was a marvellous performance.
"But Jonjo is pleased with him now and we'll wait a week or two before we decide what to do."
The same owner and trainer won the National with Don't Push It in 2010 and could have another leading hope in Sunnyhillboy, who was also a winner at Cheltenham last week in the Kim Muir Challenge Cup.
"He's also come out of the race good. He's in the National and the Irish National and he'll probably run in one of those. Nothing is set in stone yet," Berry added.
The weights continue to be headed by Synchronised on 11st 10lb, with last year's Grand National hero, Ballabriggs, 1lb behind on 11st 9lb.
Betfred make Prince De Beauchene the 9/1 second favourite for the race and he is one of six remaining entries from Willie Mullins' stable and one of 23 Irish-trained entries still in the race.
On His Own, winner of the Thyestes Chase for owners Graham and Andrea Wylie and Cheltenham Gold Cup ninth The Midnight Club are among Mullins' other entries.
Other Irish-trained contenders include the progressive Seabass, trained like the 2000 winner Papillon by Ted Walsh, and the 2011 Irish Grand National hero Organisedconfusion, the likely mount of Nina Carberry.
The Gold Cup form is also represented by fourth-placed Burton Port, Midnight Chase, who came seventh, and Weird Al, who was pulled up on Friday.
Malton trainer Malcolm Jefferson saddled a double at last week's Cheltenham Festival and he paraded his National hope According To Pete, winner of the Peter Marsh Chase at Haydock in January, at Aintree today.
Other leading contenders include the David Pipe-trained Junior, winner of the Ascot Stakes at Royal Ascot in 2010 and the Fulke Walwyn Kim Muir Handicap Chase at the 2011 Cheltenham Festival, who is a 10/1 chance with Betfred after being beaten a short-head in a Doncaster handicap chase on March 3.
The Alan King-trained West End Rocker has not run since winning the Betfred Becher Handicap Chase over the National fences at Aintree on December 3 and is 16/1 with Betfred for the big race.
Philip Hobbs has withdrawn Fair Along but intends to run Planet Of Sound.
"Fair Along will probably run in the Scottish National instead. Planet Of Sound will definitely run providing everything goes all right," the Minehead trainer told At The Races.
Others among the 18 withdrawals were Massini's Maguire, Hold On Julio, Niche Market, Stewarts House and Backstage.
The five-day confirmation stage for the Grand National is on April 9 with the final declaration stage at 10am on April 12 when there can be a maximum field of 40 runners, with the provision for up to four reserves.
The two other races over the Grand National fences, the John Smith's Fox Hunters' Chase and the John Smith's Topham Chase, close on March 27.
