Australia’s only pure white race horse may have run her last race after sustaining a tendon injury last week.

The Opera House’s career is in serious doubt after the injury; however, a full diagnosis will not be made until scans are completed in the coming days.

The rising five-year-old is raced by a syndicate put together by prolific owner John Singleton.

The Opera House’s other owners also include Australian rugby league personality Andrew Johns.

Trainer Kris Lees admitted that the popular mare’s career may well be over.

“John (Singleton’s) vet John Peatfield will scan the mare’s injured leg and then a decision will be made on her future,” Lees said.

“But she is rising five years of age and it’s very likely she will be retired to stud and not race again.”

The Opera House has had nine race starts and claimed her first win in a Wyong Maiden last start.

Lees believes that the injury could not have come at a worse time.

“It’s extremely disappointing to lose her because I had no doubt the best had yet to be seen of her on the racetrack,” Lees said.

The $270,000 yearling made headlines around the country long before she began her racing career due to her distinct colouring.

The Opera House, who made $27,000 in prize money over her nine starts, was also a three-quarter sister to champion race horse Might And Power.

The Zabeel mare will most likely be retired to a career as a broodmare should the scans confirm her suspected tendon injury.