Paul Carberry will miss the ride on Marlborough in the Tote Cheltenham Gold Cup after injuring his hand in a fall at the Festival yesterday.
Carberry injured his left hand when unshipped from Harbour Pilot in the Royal and SunAlliance Chase. He was taken to Cheltenham Hospital for X-rays before returning to the track with the hand strapped.
Barry Simpson, racing manger to the owner, said: "Paul Carberry will not ride. He has a problem with his hand. I think a horse stood on it after his fall yesterday. It wasn't through the fall he hurt it, it was what happened after.
His absence could mean that Dean Gallagher, who won the Smurfit Champion Hurdle on Hors La Loi III earlier in the week, will ride Marlborough in the feature race.
Although riding plans have not yet been confirmed, Gallagher seems the most likely candidate to partner Sir Robert Ogden's horse.
"Dean Gallagher is on standby and is the most likely replacement but I have yet to confirm that with Sir Robert," Simpson said.
For his part, Tony McCoy will be looking to put a nightmare couple of days behind him on the final day of the Cheltenham Festival today.
The champion jockey has not won on the first two days of the festival despite having a number of fancied rides and was left devastated following the fatal injury to Valiramix in Tuesday's Smurfit Champion Hurdle.
McCoy has another full day ahead of him at Prestbury Park kicking the day off by partnering Londoner in the opening JCB Triumph Hurdle for boss Martin Pipe.