Police say there are no suspicious circumstances around the death of the multiple Group One-winning rider, 31, a brother of top professional boxer Michael Katsidis.
He was due to ride Australian Derby winner Shoot Out in the Cox Plate on Saturday and the Melbourne Cup.
His death has stunned the Australian racing community, which is gearing up for the famous 2 November contest.
“He told me he couldn’t wait to get to Melbourne and that he’d be down on Thursday,” said Shoot Out trainer John Wallace. “It’s a total shock.”