White Birch will not take his place in the Eclipse Stakes (G1) July 6 after he was ruled out of the Sandown contest following an unsatisfactory blood test.
A decision on the John Murphy-trained star's participation in a clash of generations against City of Troy had been up in the air and connections will now skip the assignment with their ultra-progressive 4-year-old.
George Murphy, assistant trainer to his father John, told Racing Post: "White Birch had a blood test this morning and unfortunately it hasn't come back 100% perfect. As a result, we've decided not to travel to Sandown for the Eclipse this weekend. The horse is in good form at home and we're looking forward to the rest of the season with him."
White Birch has been a revelation this year, winning all three of his races, including when landing a first group 1 in the Tattersalls Gold Cup (G1) at the Curragh in May. That form was franked when runner-up Auguste Rodin won the Prince of Wales's Stakes (G1).
It is the second time White Birch has suffered a setback due to his blood, after he was also ruled out of that Royal Ascot contest last month.
His Eclipse absence means that City of Troy's opponents will be headed by fellow 3-year-olds Dancing Gemini and the Clive Cox-trained Ghostwriter, who finished ahead of the red-hot favorite when fourth in the Two Thousand Guineas (G1).
The next best older horse in the betting is Luxembourg, with the Coronation Cup (G1) winner one of four entries for Aidan O'Brien. A maximum field of 10 could now line up in the about 1 1/4-mile group 1.
City of Troy has shortened with race sponsors Coral and is now 2-5, having been 1-2 before White Birch's scratching.
Coral spokesperson David Stevens said in a Jockey Club press call: "We're perhaps not going to get the tilt we wanted, as older horses taking on 3-year-olds is what this race is all about. Luxembourg is now the key horse if he takes on his stablemate, who is now 2-5 (from 1-2).
"Nashwan was the same price when he did the Derby and Eclipse double, but so too was Motivator in 2005 and he couldn't do it. We're going to have an odds-on favorite—he's a Derby winner and why shouldn't he be?"
