Trained by William Muir and Chris Grassick, the four-year-old had been among the leading fancies for the midsummer showpiece but a minor setback will prevent him from lining up.
Muir told Nick Luck's Daily Podcast: "He worked superb on Saturday, we went to Charlie Hills' and he worked stunning with a very good miler.
"I walked over to meet him coming back - he was bouncing - washed him down and what have you and all was fine, but that evening I just thought he was slightly wrong behind on his off hind.
"My vet came, his testicle was pulled right up so he thinks he might have rolled in his box and tweaked his groin."
He went on: "Any horse, they are my life, like my children, so I can't run him if he's not 100 per cent.
"He'll be checked over again until we can find exactly what it is, but I told the owners I didn't even think I was going to confirm him which is gutting as he's as well as I could have him.
"He came off the gallops and I thought nothing could beat him.
"There's loads more races - we're in the Juddmonte whatever happens if it's something very simple. We were going to give him a break at some stage as we're thinking of taking him round the world at the back end of the season, so maybe this might be the enforced break.
"We've got to do whatever is right with every horse we've got."