Mark Walsh is on standby to partner Colbert Station if Tony McCoy opts to ride Double Seven in the Grand National at Aintree.

Of the JP McManus-owned duo, McCoy has admitted to having a slight preference for the latter, trained by Martin Brassil.

Should that be the case, Walsh, who is used regularly by McManus in Ireland, will get the leg-up aboard Colbert Station who unseated McCoy at The Chair jump in last year's National.

"He (Colbert Station) is all ready to go," Walsh said.

"I haven't spoken to Tony about what he's riding, though. I don't expect to speak to him until I see him at the races on Thursday (Friday AEDT) and he'll have made his decision by then.

"If he picks Double Seven then Mark will be riding ours. I've no problem with that at all.

"Mark rides most of JP's horses when Tony isn't in Ireland anyway."

The 18-time champion jumps rider, McCoy rode the McManus-owned Don't Push It to win his first Grand National 2010 at his 15th attempt.