Don Poli was ruled out of next Friday's Gold Cup yesterday and it now appears that both Gigginstown and Gordon Elliott will potentially revise their team for the big race - though this is not certain.
The owner's racing manager, Eddie O'Leary, told this newspaper that heat was detected in Don Poli's leg yesterday morning, a similar predicament which befell Don Cossack, which Gigginstown subsequently retired.
He said: "We'd be aiming at having him back late next season but a leg is leg."
Elliott revealed in his Betfair blog: "Don Poli has picked up an injury and will not make it to this year's Festival. We are all very disappointed as he was in great form and we were really looking forward to him running."
With Michael O'Leary's main runner in the race now Outlander - Don Cossack, Road To Riches and Valseur Lido have already been ruled out - he will consider bringing in Empire Of Dirt, which was expected to run in the race the businessman sponsors, Thursday's Ryanair Chase.
Eddie O'Leary added: "We have to get over this news first and no decision on our Gold Cup team will be made at this time. Rerouting Empire Of Dirt is not by any means certain."
Don Poli was a leading fancy too for the BoyleSports Irish National, having been pulled out of the Aintree National due to a disagreement over his weight.
Don Poli's blow means that, from the past two Gold Cups, Djakadam is the only placed horse which will take his chance next week, as 2015 winner Coneygree is also sidelined.
Quitting JP McManus' racing manager Frank Berry says Bon Papa will likely run next week, but it has yet to be decided as to whether he will tackle the Albert Bartlett or Neptune for trainer Willie Mullins, with Mark Walsh set to ride.
Meanwhile, Adrian Maguire has refuted suggestions he is quitting training. The former rider enjoyed a winner at Thurles on Thursday and admitted afterwards that he was struggling to make ends meet.
However, he does not want to call it a day. "My intention, I must stress, is to stay doing what I love - training horses. As I said, it is extremely tough, and something has to change, but I'm hoping getting a couple of new owners will turn the situation around."
Kieren Fallon says he is hoping to embark on a training career in the near future. The legendary rider, citing depression, quit the saddle last summer.
He told Dubai Racing Channel: "I will soon, I think I'll start (training). I know I'm going back to work for William Haggas in the mornings. I've a few options, a few other things I have to do as well.
"It's going to be exciting. I'd like to start training or even if I didn't myself, I'd love to join somebody and work with a good trainer."
Captain Guy Disney, the first rider to win a race under rules in Britain with a prosthetic leg, pulled off a military race double at Sandown yesterday as Rathlin Rose burst clear in the Grand Military Gold Cup.
Disney, an Afghan war veteran, won the Royal Artillery Gold Cup three weeks ago and said: "It's magical; what a lovely horse."
TG4 will screen its annual preview of the Festival today at 7.15, repeated on Monday at 6.25pm. It includes a feature on jockey Roger Loughran.