Victorious with the AP McCoy-ridden Don’t Push It in 2010, he hopes the track dries out for last year’s Cheltenham Gold Cup runner up who runs in the colours of JP McManus.
A faller in February’s Irish Gold Cup, Minella Rocco has subsequently had a wind operation to assist his breathing after connections purposely avoided a second tilt at Cheltenham’s blue riband race.
“The ground got very heavy at Cheltenham and, as we all know, Minella Rocco has got a wind problem and that ground wouldn’t help him, so we saved him for the Grand National,” he said.
“So long as we get good ground, we’ve a good chance.
“He’s won over four miles, so he just has to get another quarter of a mile.
“Top-weight isn’t ideal, but that’s the way it is and he’s a big horse, so hopefully he can carry it. He jumps well and keeps galloping, so the National was always at the back of my mind.
“You need a lot of luck and obviously a horse that jumps and stays. On paper, Minella Rocco would be a better horse than my previous winner Don’t Push It, but everything has to go right.”
Burdened with 11st 10lb, O’Neill can, however, draw comfort from the fact that Many Clouds prevailed in 2015 carrying just one pound less.
Minella Rocco is likely to be ridden by weighing room veteran Noel Fehily with Barry Geraghty sticking with Irish challenger Anibale Flyer who was third to Native River in last month’s gruelling Gold Cup.
Popular jockey Bryony Frost’s Milansbar is now a confirmed runner for trainer Neil King. Yet, following the latest declarations, Yorkshire hopes appear to rest with the Sue and Harvey Smith-trained I Just Know as they bid to replicate the victory of Auroras Encore five years ago.
It appears, depending how chief handicapper Phil Smith asseses all the horses on 10st 4lb, that they need three horses to be withdrawn by Friday morning’s final cut-off for Delusionofgrandeur to make the 40-runner line-up.
Five need to be withdrawn for Cheltenham Festival third Vintage Clouds to qualify, an unlikely proposition so close to the big race.
Meanwhile high-profile jockeys without confirmed mounts include champion jockey Richard Johnson and Derek Fox who was victorious 12 months ago on One For Arthur.
In other developments, Seeyouatmidnight has been purchased by David and Patricia Thompson of Cheveley Park Stud and will run in their colours at Aintree on Saturday.
The 10-year-old, trained in the Scottish Borders by Sandy Thomson, had been owned by his wife, Quona.
The Thomsons bought Le Mercurey and Highland Lodge the week before last year’s race, with the former 12th and the latter pulled up.
Party Politics famously won the National in their pink and purple colours in 1992.
Thomson said: “Anthony Bromley (bloodstock agent) approached us at Newbury. It was a long drive home thinking about it, but in the end it wasn’t really a difficult decision.”
He confirmed North Yorkshire jockey Brian Hughes keeps the ride.
However Cause Of Causes, a three-time Cheltenham Festival winner and runner-up in last year’s Grand National, has been retired.
The decision to call time on the Gordon Elliott-trained 10-year-old’s career came on the back of a disappointing performance in last month’s Glenfarclas Cross-Country Chase, which he previously won in 2017.
His other two victories at Cheltenham came in the National Hunt Chase in 2015 and the Kim Muir Handicap Chase in 2016 while he competed at the last six Festivals.
“He came back a little bit sore from Cheltenham and he’s been such a good servant we thought we’d retire him,” said Frank Berry, racing manager for aforementioned owner JP McManus.
“To compete at six Festivals in a row is unbelievable.”