Tiger Roll is no better than 50-50 to bid for an historic third victory in the Grand National with part-owner Eddie O'Leary disappointed with his weight of 11 stone 10lb (74kg).

The Gordon Elliott-trained 10-year-old became the first horse since Red Rum to claim back-to-back editions of the world's most famous steeplechase last April.

He is the clear favourite to emulate the Ginger McCain-trained legend by becoming a three-time winner.

But O'Leary, brother of Gigginstown House boss Michael, has repeatedly said Tiger Roll would only bid for another National if connections were satisfied with his rating, and the immediate reaction to his mark of 170 and the compression of the handicap was one of frustration.

Tiger Roll is due to make his first competitive appearance since Aintree last spring in Sunday's Boyne Hurdle at Navan.

"Hopefully he comes through Navan on Sunday OK, then goes on to Cheltenham and hopefully that all goes OK and if he's OK at Cheltenham then we'll make a choice.

"It (the weight) is a massive factor. We've said the whole way through this horse is on a very unfair rating.

"The last time this horse ran in a (regulation) chase was two and a half years ago and he pulled up off 150. He's obviously improved for the Grand National discipline and cross-country, but to rate this horse as a winner of a Gold Cup is ridiculous."

O'Leary insists he has no problem with Tiger Roll being joint topweight alongside his Irish Gold Cup-winning Gordon Elliott-trained stable companion Delta Work.

He feels it is unfair Tiger Roll must concede weight to Cheltenham Gold Cup winner, Native River.

"Tiger Roll is a very, very special horse but is he a Gold Cup horse? A genius like Gordon Elliott has never even considered entering him in the Gold Cup," he said.

"We obviously would love to see Tiger Roll to go for three in a row, but we're very vocal about the fact that it (handicap) has to be compressed. It's only been compressed 1lb.

"The welfare of the horse we feel is far more important to us than the race.

"The Grand National is the biggest race in the world, it's bigger than any one horse."

Elliott was more accepting of Tiger Roll's rating.

"A blind man would know he's going to carry 11st 10lb," he said.

"We were obviously hoping for a pound or two less.

"Everyone has got their own opinion. If it's left to me he'll run."