Hector Barbera is in doubt for the forthcoming Australian MotoGP after breaking his collarbone on the second lap of Sunday's Japanese Grand Prix.

The Aspar Ductai rider was knocked out in the accident, after which he was taken to the circuit medical centre and then to hospital, where a CAT scan revealed the right-collarbone fracture.

The initial signs are that Barbera, ninth at the time of his accident, will stay in the hospital for between 24 and 48 hours.

Barbera missed several races after fracturing two vertebrae in the 2008 250cc Motegi event.

The Australian Grand Prix at Phillip Island will take place from October 14-16.