Australian sprinter Houtzen has an elevated temperature which has ruled her out of the Group One Nunthorpe Stakes at York.
Owners Aquis Farm had planned to pay a late entry to put the mare in Friday's 1000m-race but have announced she will now be saved for a Group One race in Ireland.
Houtzen was unplaced in the King's Stand Stakes at Royal Ascot in June after stumbling out of the barriers but ran an eye-catching second to Battaash in the King George Stakes at Goodwood.
"Due to an elevated temperature, #Houtzen will unfortunately miss the upcoming Gr.1 Nunthorpe Stakes, but will now be aimed at the Gr.1 Flying Five @curraghrace in September," Aquis said on Twitter.
Battaash is the second favourite for the Nunthorpe behind Ten Sovereigns who is in line to represent Coolmore in the $14 million Everest at Randwick in October.