Triple Group One winner Gailo Chop's racing future is in doubt with the seven-year-old re-injuring a tendon.

The original injury kept him off the scene for 18 months in 2016/17.

He had been the favourite for the Doomben Cup on Saturday week with the Anthony Freedman-trained Ambitious now leading the market at $4.40.

Raced by Terry Henderson's OTI and the winner of the 2015 Mackinnon Stakes for French trainer Antoine de Watrigant, Gailo Chop has been trained by Darren Weir to Group One wins in the 2017 Caulfield Stakes and the Ranvet Stakes earlier this year.

In his most recent start, Gailo Chop ran second to Winx in last month's Queen Elizabeth Stakes at Randwick.

His stablemate, 2015 Toorak Handicap winner Lucky Hussler, has been ruled out of Saturday's Doomben 10,000 with a foot abscess and will now be aimed at the Goodwood in Adelaide a week later.

In a bad day for the stable, Weir says Amerock also has a foot issue and will come out of Saturday's South Australian Derby denying jockey Harry Coffey the chance to add to his first Group One victory on Sopressa in last week's Australasian Oaks at Morphettville.