Paul Carberry will ride Florida Pearl in the £100,000 Nicholson Champion Chase at Down Royal on November 6th.
Carberry has been chosen to replace Ruby Walsh who fractured his right shin bone in an accident in the Czech Republic on Sunday and will be on the sidelines until Christmas.
Florida Pearl's regular rider Richard Dunwoody is also on the sidelines recovering from an operation on his arm and is forecasting a February return to action.
Carberry rode Florida Pearl in a recent schooling hurdle at Punchestown. Afterwards trainer Wille Mullins and owner Archie O'Leary agreed on Carberry as the man to step into the hot seat.
"Paul liked the horse, got on well with him and his style of riding should suit. We put it to Paul and he agreed that he will ride the horse if he is free," Mullins said yesterday.
He added: "Florida Pearl is in great form and I was very happy with his Punchestown work. I am more than delighted with how forward he is."
Florida Pearl hasn't raced since finishing runner-up to Imperial Call at the Punchestown Festival. Before that he was beaten for the first time in a race he completed when third to See More Business in the Cheltenham Gold Cup.
Carberry rode Dorans Pride in that race and also rode Michael Hourigan's horse in the Kerry National at Listowel last month.