Luke Durbridge’s defence of his Australian Road and Time Trial titles is in doubt after he failed to start the Williamstown Criterium, the final stage of the Mitchelton Bay Cycling Classic series.

The Orica-GreenEdge rider won stage three of the series, the Portarlington Criterium, but he was forced out of stage four with a sore throat.

Under-23 world time trial champion in Copenhagen in 2011, Durbridge has won the elite men’s time trial title at the Australian championships in each of his first two seasons as a professional. This year’s race takes place in Ballarat on Wednesday, while the road race takes place next Sunday.

His directeur sportif at Orica, Matt Wilson said he is by no means a certainty to start Wednesday’s time trial: “No, not at all,” Wilson told the Sydney Morning Herald. “Last night [Saturday] he was saying there was a little bit of something in his throat, and then he woke up this morning saying it was really, really sore, so there was no way we were risking him today. We'll nurse him in the next couple of days and hope it doesn't get any worse.''