The Storyteller was the only retreat as the final field of 40 horses – led by Cloth Cap – was named Grand National on Saturday.
This means that Blaklion is the last horse to be guaranteed a race in the big race on Aintree.
The winner of Grand Neck and Welsh Grand National’s Secret Reprieve are the main reserves.
Patrick Mullins will ride leading Burrows Saint candidate for his father coach Willie Mullins.
Stable jockey Paul Townend will miss the ride after suffering a foot injury.
The reserve can make the lineup if any of the candidates are drawn before 1pm BST on Friday.
Last year’s Grand National was canceled due to the Covid-19 pandemic, while this year’s competition will be held without spectators.
Police are stepping up patrols around the meeting, residents near the Merseyside track warned not to gather in groups larger than six in their gardens during the race.
Cloth Cap, coached by Jonjo O’Neill, is the 4-1 favorite to bring owner Trevor Hemmings a record fourth win in green, yellow and white.
Tiger Roll returns to Aintree – but not National
Double Grand National winner Tiger Roll will return to the scene of his biggest triumphs on Thursday – but in the second race at Aintree.
He ran into an 11-year-old Betway Bowl, where rivals will be Clan Des Obeaux and Native River.
It is the main race of the first day, culminating with Saturday’s National.
Tiger Roll was withdrawn last month from National, which he won in 2018 and 2019.
Owners Michael and Eddie O’Leary said they were dissatisfied with weight the horse was assigned.
The Tiger Roll became the first horse since Red Rum in the 1970s to win three consecutive Grand National runs when it triumphed in 2019.
He is currently coached by Denise Foster while Gordon Elliott is serving a suspension, he recorded the fifth victory of the Cheltenham Festival in March.
Thursday’s race is a three-mile equilibrium weight competition, compared to the National’s four-and-a-quarter mile, which is a handicap in which 40 runners carry different weights.
Clan Des Obeaux is a two-time winner of King George VI Chase, and Native River won the 2018 Cheltenham Gold Cup.
Among the rivals are this season’s runner-up King George who is patiently waiting, along with Ace, Mr. Fisher, Clondaw Castle, Real Steel and 100-1 outsider Militaria.
Former Buveur D’Air hurdles champion, coached by Nicky Henderson, is running at Aintree Hurdle after missing last month’s Cheltenham festival.
Billaway, Cat Tiger and Dashing Perk among the runners were the first to race in a meeting over national fences while amateur jockeys battled Foxhunters Chase.
The race is run in the name former Aintree president Rose Paterson, who took her own life last year.
On Saturday, her husband, North Shropshire MP Owen Paterson, is launching the Rose Paterson Trust, a charity that supports suicide prevention projects.