Ruby Walsh has yet to decide which of Willie Mullins' team he will ride in the Crabbie's Grand National at Aintree on Saturday week.

Mullins still has five in the Grand National - Sir Des Champs, Ballycasey, Turban, Boston Bob and On His Own - but at this stage the Closutton maestro's stable jockey cannot say which he will partner.

However, he played down his chances of winning for a third time after Papillon in 2000 and Hedgehunter in 2005 as he considers all of the champion trainer's five possibles to be "longshots".

"We have five in it. Sir Des Champs is Gigginstown's so I don't know what Bryan (Cooper, their retained rider) is doing," Walsh told At The Races.

"We've Ballycasey, Turban, Boston Bob and On His Own. I'd imagine Patrick (Mullins) will ride On His Own.

"They are five long-shots and any of them, on their best day, could run a big race, but whether their best days are behind them or not now is questionable."

After enjoying a superb Cheltenham Festival with seven winners, Mullins is a serious contender to being crowned champion trainer in the UK for the first time to add to his many Irish title triumphs.

A strong raiding party including Champion Hurdle heroine Annie Power and the brilliant Vautour is likely to be in action at Aintree next week and Walsh believes just being in with a chance of being British champion is a "massive achievement" for Mullins.

"Even to be in with a chance of winning it is incredible and you've seen how much money he has amassed here in Ireland as well," said the jockey.

"He is a brilliant trainer, he's a gentleman to work for and it would be a massive achievement, but he's very good at putting his horses in the right races.

"Doing that is a huge thing and Willie is brilliant at it."