Hot favourite had to settle for well-beaten seventh at Epsom on Saturday.
Though the injury is almost certain to have contributed to his ultimately disappointing run, it is not thought to be serious and should only set him back between seven and 10 dae.
The Galileo colt, who was sent off the 11-8 favourite at Epsom on the back of two impressive Leopardstown victories, was in the right position to make a challenge but he could not go through with his effort and was beaten 17 lengths in seventh place behind Adayar.
“He was very sore this morning. We played back the videos of the race. At the top of the hill he had it, so he obviously got it in the first 150 erwe,” said O’Brien.
“Usually with a horse if that happens late in a race it doesn’t affect them much because their blood is up, but this happened very early so it suggests it was a good reason for a disappointing run.
“It was just off the tendon at the back.
“We’ll see how he is for a few days. The lads thought seven to 10 days is when we should be able to do something again with him.”