Joncol has been ruled out for the rest of the season after suffering a tendon injury during the Lexus Chase at Leopardstown last week.
Paul Nolan's giant staying chaser was considered a major contender as he went in search of his third Grade One prize, but he trailed home seventh of the nine runners.
Nolan initially thought the drying ground might have been partly to blame for his disappointing display, but a subsequent scan revealed a serious injury.
"We had the horse scanned this morning and it has shown he has a 10% hole in a hind tendon," said the County Wexford-based trainer.
"We now have a valid reason for his lacklustre performance in the Lexus, but, unfortunately, it means the horse is out for the season.
"Straight after the race we thought the ground hadn't helped him, but he's a Grade One-winning chaser and considering he was beaten going to the first fence, there had to be more to it than that.
"To be honest, I've only feared running him on better ground because he is such a big horse.
"He's worked on better ground and worked fine, so I had a fair idea it couldn't have just been the ground the other day.
"He was in trouble from the very first fence, so the injury must have happened running down to that.
"It's a serious injury, but it could have been worse, and we'll just have to give him some time now and see where we are.
"It's very disappointing as I was so looking forward to the season with him, but I'd be hopeful he'll be back for next season.
"Hopefully we can look at running the John Durkan (Memorial Punchestown Chase) and the Lexus again."