Geraghty suffered a hairline fracture of his left shin bone in a fall at Downpatrick on Sunday.
As a result he will miss the Grand National for the first time since 2000 and will also be absent from the Irish equivalent at Fairyhouse.
With Punchestown not starting until April 28, Geraghty still hopes to be back in time for the finale to the Irish season.
“I saw my surgeon this morning and he will reassess things in four weeks,” said Geraghty.
“At the moment I’m hopeful of making it back in time for Punchestown.”
Meanwhile Saphir Du Rheu will be given options over both hurdles and fences at Aintree’s Grand National meeting. After falling on two of his first three starts over fences, the Paul Nicholls-trained gelding reverted to the smaller obstacles to win the Cleeve Hurdle at Cheltenham in January to set up a World Hurdle tilt at the Festival.
The six-year-old was sent off favourite to carry the Stewart family silks made famous by Big Buck’s to Cheltenham glory, but he came up just short, filling the runner-up spot behind all-the-way winner Cole Harden.
Although Saphir Du Rheu’s immediate target is uncertain, owner Andy Stewart sees his long-term future back over fences. He said: “He’ll be entered in the three-mile hurdle at Aintree (Liverpool Hurdle) that Big Buck’s won four times and the three-mile novice chase, which Big Buck’s also won, actually.
“He ran very well at Cheltenham to finish second and I was very pleased for Warren Greatrex, who won the race with Cole Harden.
- Dubai World Cup favourite California Chrome delighted his connections in a 5am spin on the dirt track at Meydan on Tuesday. Working under the floodlights, the chestnut cast a spectacular sight in front of camera crews and reporters who gathered for the exercise.
The 2014 Kentucky Derby and Preakness Stakes winner blew out over a circuit of the track. Sherman said: “My son Alan’s been out with him every morning and said he came off the track bouncing this morning. He seems to be handling the surface well and this is an opportunity to run his race and put on a big show.