Kalderon is undergoing an operation on a fractured shoulder at Troyton Veterinary Hospital in Kildare following a fall at Punchestown.
The eight-year-old gelding sustained the injury when taking a tumble at the eighth fence in the Buck House Novice Chase on Thursday.
“They are operating on him now and it will later this evening before we have any news on whether it has been successful or not,” said Tipperary trainer Tom Hogan.
“It can be fixed. It’s the only part of their body that can take a break for the horse to go back to full fitness – so, please God, he’ll be all right.”
Kalderon has won 15 of his 45 starts, amassing £222,000 (€284,480) in total prize-money, and has been successful on the Flat, over hurdles and over fences.