DUAL Melbourne Cup-winning jockey Kerrin McEvoy is set for an indefinite spell on the sidelines after breaking a hand in freak accident.

Scans on McEvoy's right wrist revealed a break after he was injured cantering race favourite Sugar Bella to the barriers before the Catanach's Handicap on Saturday at Randwick.

"The horse just jinked sideways on the way to the barriers, my fingers got twisted and I heard a crack," McEvoy said.

McEvoy was examined by the club doctor at the 1400m start and was immediately stood down.

The South Australian underwent surgery on Sunday to have either a plate or screws inserted.

McEvoy is unsure how long he will be out of action.

Caulfield trainer John Sadler will on Monday face the Racing Appeals and Disciplinary Board on a charge of improper conduct.

Sadler has pleaded guilty to the charge.

The charge stemmed from Sadler's conduct before and after the stewards ordered the late scratching of his horse Observational from the Group 3 Eclipse Stakes at Sandown on November 18.

Stewards allege that comments made by Sadler on the day of the race to chairman of stewards Terry Bailey in telephone calls at approximately 8.17am and 11.45am and in person to Bailey and deputy chairman of stewards Robert Cram in the stewards room at approximately 1.20pm constitute improper conduct.

Stewards are continuing their inquiry into "the circumstances that required the withdrawal of Observational".