Paul Townend is facing a spell on the sidelines after fracturing his left collarbone in a fall at Navan.
The rider, who is currently leading the race for Ireland's jockeys' title, sustained the injury when his mount Indian Buck fell fatally in the concluding Headfort Handicap Chase.
Townend is nine wins ahead of Davy Russell in the championship battle but his rival is also out of action at the moment after suffering a wrist injury.