So You Think has been retired to stand at stud in Australia after lameness ruled him out of the Coral-Eclipse at Sandown on Saturday.
The Aidan O'Brien-trained six-year-old would have been aiming to land back-to-back renewals of the Group One contest over a mile and a quarter, which was due to be his final run before returning to his native Australia.
O'Brien told www.coolmore.com: "So You Think is an extraordinary horse and it was a real privilege to have had him here at Ballydoyle on loan from Australia."
Formerly trained in Australia by the legendary Bart Cummings, for whom he won two Cox Plates, the giant So You Think moved to O'Brien's Tipperary base after Coolmore bought a controlling interest.
He was to add five Group One success to his CV under O'Brien's care, to go with the five he claimed Down Under.
Coolmore's Tom Magnier said: "It's a big disappointment that he'll miss the Eclipse, but he's had a wonderful racing career and now it's time for him to shine at stud.
"His book reads like a who's who of all the best mares and breeders so he'll get the best possible start."