For the second time the prestigious event is named in honour of the former leading amateur rider, who died aged 41 in July of last year.
McNamara was paralysed following a fall at the Cheltenham Festival in 2013, when he fractured vertebrae in his neck when Galaxy Rock came down at the first fence in the Fulke Walwyn Kim Muir Challenge Cup.
Auvergnat is trained by McNamara's close friend and long-time ally Enda Bolger and carries the colours of leading owner JP McManus, who provided him with numerous big-race victories.
Bolger said: "It's a great race to be part of and obviously it would be very poignant if we could win it."
Auvergnat, who is a best priced 8-1 with Sky Bet, has won three times over fences and makes his first appearance in nearly four months.
"It's his first run since June, but he's in good form and we're hoping for a good run," the trainer added._Auvergnat bids to defy a 118-day layoff at Limerick on Sunday _(PA)
"He won't mind the soft ground and he gets the trip well."
Total Recall, the general 4-1 favourite, makes his debut for the formidable combination of Willie Mullins and Ruby Walsh.
The eight-year-old won twice over hurdles and once over fences for Sandra Hughes, who retired from training in the spring.
With a rating of 129, he has crept in near the bottom of the 16-strong field and the bookmakers are taking no chances, installing him as a best-priced 4-1 favourite.
The champion trainer's son and assistant, Patrick Mullins, said: "He came to us during the summer and obviously has some good form from when he was with Sandra Hughes.
"He's at the right end of the weights and we've been happy with his work at home.
"He has some good form on soft ground - I remember him running a good race behind Anibale Fly and Martello Tower in a beginners' chase in Navan one day.
"It looks as though the trip will suit him and there's some good prize-money on offer, so we'll give it a go and see what happens."
The weights are headed by the Mouse Morris-trained Alpha Des Obeaux, who won twice as a novice over fences last season and was fourth in the RSA Chase at the Cheltenham Festival.
The Fethard-based trainer also saddles 2016 Irish Grand National hero Rogue Angel and recent Listowel scorer Dromnea.
Morris said: "Alpha Des Obeaux has to give the weight away, but he seems in good form and we're hoping for a big run.
"Three miles around here is probably sharp enough for Rogue Angel, but when he needs three miles plus you're limited as to where you can go with him.
"Dromnea won well the other day. He's gone up 7lb for that but hopefully he has an each-way chance.
"It would be hard to split him and Alpha. I think wherever one finishes the other one won't be far away."
Raz De Maree won this prestigious event in 2012 when trained by the late Dessie Hughes.
Now in the twilight of his career at the age of 12, he makes his first visit to Limerick since that victory of five years ago for Navan-based Gavin Cromwell.
Cromwell said: "He's a good bit higher in the weights than when he won it, but for a horse of his age he seems in great form.
"We wouldn't want the ground to dry out too much as the more of a stamina test it is, the better it will suit him.
"He won the Cork Grand National last year and I'd imagine we'll go there again before having another crack at the Welsh National at Chepstow. He was second in it to Native River last year."
Other contenders include Joseph O'Brien's trio of Arkwrisht, Slowmotion and King Leon.