Ruby Walsh expects to find out next week how long he will be on the sidelines for after aggravating the broken leg injury which had kept him on the sidelines for the previous four months in a fall at Cheltenham.
The winning-most jockey in Festival history will miss the final two days of the showpiece meeting after parting company with Al Boum Photo at the penultimate fence in the second race of the day, the RSA Insurance Novices' Chase.
He was taken to Gloucester Royal Hospital for X-rays and further assessment. The 38-year-old rider only returned to competitive action last Thursday, after suffering his original injury at Punchestown on November 18.
Walsh told Racing UK: "My right leg is in a cast and the fall opened the fracture at the back.
"I won't know the full extent until Tuesday."
A statement issued by his sister and agent, Jennifer, said: "Unfortunately he has aggravated a recent leg injury and will see his consultant in Dublin next week for further assessment."
It had been feared earlier in the day the leg could be broken again, but trainer Willie Mullins said the injury was not as serious as first thought and even raised the possibility of Walsh returning to the saddle before the end of the season.
Mullins explained: "The information I have is that he has a stress fracture on the old break.
"He might need a cast for maybe three weeks or a month and then he could be back.
"Instead of being back for Galway, he could be back for Punchestown (at the end of April). That would be a fantastic result."
The Irish champion trainer said Paul Townend is likely to come in for the ride on Un De Sceaux in Thursday's Ryanair Chase.
Asked about riding arrangements for Friday's Timico Gold Cup, in which Walsh was set to partner Killultagh Vic, Mullins added: "I haven't really thought about it, to be honest. I'll leave it up to the jockeys.
"Paul will be offered the ride on Killultagh Vic, but he might want to stay on Total Recall, in which case David (Mullins) or Patrick (Mullins) could ride Killultagh Vic. We'll see."