The two-time Irish Gold Cup winner Carlingford Lough, trained by John Kiely, will run in either the Irish National or the Punchestown Gold Cup.
Last year's runner-up The Last Samuri now has top weight of 11st 10lb.
The 33-1 chance Carlingford Lough was among nine withdrawals, leaving a total of 70 entries, with a maximum line-up of 40 announced on Thursday.
Foxrock, trained by Ted Walsh, was rated a 20-1 shot for the race by bookmakers. Vieux Lion Rouge is the general 10-1 favourite.
As it stands the 40th horse in the field is the David Pipe-trained La Vaticane, one ahead of stablemate Doctor Harper.
The nine withdrawals are: Carlingford Lough, Alelchi Inois, Foxrock, Maggio, Ziga Boy, The Romford Pele, Straidnahanna, Sizing Coal and Vics Canvas.
Ziga Boy is likely to miss the whole of next season and be aimed at a potential return in autumn 2018.
Meanwhile, Derek Fox - who was injured in a fall on 9 March - has been passed fit to ride One For Arthur in the National for trainer Lucinda Russell.
The three-day Grand National meeting begins on Thursday, with Cue Card expected to be among the main attractions.
Colin Tizzard's popular chaser, who fell at the third-last fence for the second successive year in the Cheltenham Gold Cup in March, will bid to win the Betway Bowl (14:50 BST) again after succeeding 12 months ago.
The Paul Nicholls-trained Silviniaco Conti, winner in 2014 and 2015, could be among his rivals.
Champion hurdler Buveur D'Air heads entries for the Aintree Hurdle (15:25), alongside stablemate and Cheltenham runner-up My Tent Or Yours, with previous winners Jezki and The New One other possibles.
On The Fringe and Pacha Du Polder head contenders for the Foxhunters' Chase over the Grand National fences.
Enda Bolger's On The Fringe has won the last two renewals, but could only finish fourth behind the Nicholls-trained Pacha Du Polder at Cheltenham.
Top weight Carlingford Lough and Foxrock have both been ruled out of Saturday's Grand National at Aintree.