The search is on to find a stud farm to stand triple Group 1 winner Hitotsu after the curtain was officially drawn on the four-year-old's racing career on Tuesday.

The son of Maurice, who has not started since winning the ATC Derby at Randwick in April last year, sustained a leg injury that subsequently became infected.

The latest leg problem, which followed a suspensory injury last year, was treated and the Ciaron Maher and David Eustace-trained star is recovering but connections have aborted the dream of seeing him resume his racing career as an older horse.

"While it is incredibly disappointing, he provided us with some of the most memorable moments we've enjoyed on a racetrack in his short career," Maher said.

"He is one of the most talented horses I've ever trained and I hope one day I can train his progeny."

Hitotsu started his career with Cranbourne trainer Wendy Kelly, who paid $100,000 for him at the 2020 Gold Coast Yearling Sale, before he was bought by Ozzie Kheir and partners late in his two-year-old season.

After winning a 1350m Donald maiden at his first start for Maher and Eustace, Hitotsu finished fifth in the Caulfield Guineas before winning Group 1 races at what would prove to be his final three starts.

After a brilliant win in the Victoria Derby (2500m) he was spelled and returned to win the Australian Guineas (1600m) before his fighting win in the ATC Derby (2400m) and retires a winner of half of his eight starts and $3,179,250 in stakes.

"Hitotsu has taken us on an amazing journey in such a short period of time and showed that special horses can be trained in an unconventional way and that's all credit to the stable that weren't afraid to try something different," Kheir said.

"We will now start the process of finding him the best place to continue his next chapter and follow his progeny for many years to come."

Hitotsu was offered at Magic Millions by Arrowfield Stud which, in April, will sell a younger half-sister by Castelvecchio at the Inglis Easter Yearling Sale.