Ruby Walsh will miss the Grand National after suffering a wrist injury in a fall at Aintree.

The jockey was due to partner the Willie Mullins-trained Sir Des Champs in a bid to win the world's most famous steeplechase for a third time but fractured his wrist in a fall on Friday.

In his absence leading female amateur Nina Carberry will ride Sir Des Champs.

"He has a small fracture of his wrist and a lot of bruising, so he won't be riding on Saturday (Sunday AEST)," Walsh's sister and agent Jennifer Walsh told Press Association Sport.

"It's disappointing, but he's walking and talking and any day you can do that is a good day."

Ireland's champion trainer Mullins was quick to make alternative riding plans.

"Nina Carberry will ride Sir Des Champs and Paul Townend will ride Yorkhill and Douvan," he said.