Minella Rocco is a significant absentee after 13 horses were scratched from the Coral Welsh Grand National at Chepstow.
Winner of the National Hunt Chase at last season's Cheltenham Festival, Jonjo O'Neill's charge made a promising reappearance at Prestbury Park in November, but fell at the last in a Listed event won by Grand National hero Many Clouds at Aintree on Saturday.
The six-year-old had been a general 12-1 second-favourite for Chepstow's showpiece event on December 27.
Ante-post favourite Carole's Destrier is one of 89 horses still in contention.
The Neil Mulholland-trained eight-year-old ran a fantastic race to finish a close second behind Native River in last month's Hennessy Gold Cup at Newbury.
Native River has been left in by Colin Tizzard, but connections have previously suggested he is unlikely to take his chance.
Warren Greatrex is looking forward to fielding Warrantor in the three-mile-five-furlong contest.
Having finished second in his final outing of last season at Southwell, the son of Turtle Island occupied the same position on his return to action at Cheltenham last month.
Greatrex said: "Warrantor is in really good form and I was chuffed to bits with how he came out of that race at Cheltenham. He looks an absolute picture.
"The plan is to go for the Welsh National and go from there. I think the conditions of the race will suit him down to the ground. He likes it soft and stays very well, so all routes lead there.
"They go quite hard in the Welsh National and he will love every minute of it, picking horses off.
"He is rated 136 so I would like to think he would get in."
Other leading contenders include Kerry Lee's Bishops Road, the Evan Williams-trained Firebird Flyer and O'Faolains Boy from Rebecca Curtis' yard.
A strong Irish contingent features Jim Culloty's Cheltenham Gold Cup winner Lord Windermere, Noel Meade's Wounded Warrior and Gordon Elliott's pair of Empire Of Dirt and Ucello Conti.