Mullins replaces Irish champion jockey Paul Townend, who picked up a foot injury at Fairyhouse last weekend which also saw him miss Monday’s Irish Grand National.
In the immediate aftermath, Willie Mullins was in no rush to rule Townend out of Aintree – but as each declaration stage passed for Thursday’s and Friday’s cards, hopes faded he would make it back in time.
Instead, the champion trainer has called on his son – who has ridden more winners as an amateur in Ireland than anyone else and if not for his battle with the scales would surely be a professional.
Looking forward to Saturday, Mullins said: “It’s fantastic to pick up the spin on him.
“Obviously Paul hasn’t recovered from the fall he had in Fairyhouse.
“The weight (10st 13lb) is quite light for me, but it’s just enough.
“He’s in great form at home. I got a sit on him in Haydock this (Thursday) morning – and he ticks a lot of the boxes.
“He’s the right age as an eight-year-old; he has the right kind of weight and he’s progressive, with only nine runs over fences.
“I’m really excited to be sitting on him.”
With the doubt over Townend and his weight issue, it was a case of Burrows Saint or nothing for Mullins – but he was never counting his chickens, especially after amateurs were ruled out of last month’s Cheltenham Festival because of coronavirus restrictions.
“I’ve lived with Willie long enough to know not to ask any questions and to just wait until declarations,” he said.
“It was in the back of my head that I might get the ride. I saw the weight was doable, and I was watching it from then and got confirmation this morning.
“I did not expect to be able to ride a horse with a live chance in the Grand National. Ever since I was seven or eight and I read a book on the history of the Grand National, this was the race.
“It was disappointing not to be at Cheltenham. As it turned out, I didn’t miss a winner, which made it slightly easier.
“To get a ride in the National more than makes up for that, definitely.
“Some people like the Gold Cup, but this was always the race I wanted to have a crack at – it does not get any better than this.”
No amateur has won the National since Marcus Armytage on Mr Frisk in 1990, but Burrows Saint is second-favourite with some bookmakers based on the fact he won the Irish Grand National two years ago.
“In the National, game plans can go out of the window pretty quickly, but in the Irish National Ruby (Walsh) rode him fairly handy and with a bit of daylight. After that, we’ll see where Lady Luck takes you,” said Mullins.
“I was second on a horse called Boxer George in the Foxhunters (in 2011). That’s the closest I’ve come to a winner over the fences.”
Bristol De Mai topped the weights after the final 48-hour stage, which left Evan Williams’ Welsh National winner Secret Reprieve as only second reserve.
“We’ve had a lot worse news regarding horses – we knew there was a chance that would happen, so there’s no point worrying about things we can’t control,” Glamorgan trainer Williams told Sky Sports Racing.
“He’s safe and sound, and that’s always the main thing. He’ll go home with Mr and Mrs Rucker (owners) now – and we’ll think about next year.
“We took a punt about getting in the National, and it’s not going to work out. That’s the way it is.
“The great thing about missing out on getting into the National is they dropped him 2lb for anywhere we want to go now next year. Every cloud has a silver lining.”
Dan Skelton’s Blaklion was the beneficiary of The Storyteller’s no-show, and creeps in as number 40. The first reserve is John McConnell’s Some Neck, with Kauto Riko third reserve and Fagan the fourth and final one.
Ante-post favourite Cloth Cap will aim to give Trever Hemmings a record fourth win in the race following the successes of Hedgehunter, Ballabriggs and Many Clouds – and his trainer Jonjo O’Neill is chasing his second National, having won with Don’t Push It.