Hector Barbera is recovering after surgery to plate his broken right collarbone.
The Aspar Ducati rider sustained the injury on the second lap of last Sunday's Japanese Grand Prix, during which he was also knocked out.
Upon returning to Spain, Barbera was admitted to the Clínica USP Dexeus in Barcelona, where he underwent surgery on Wednesday.
According to the official MotoGP website, Barbera 'can begin light physical activity within five days. The recovery time however is not sufficient enough to allow the Mapfre Aspar rider to participate in the Australian Grand Prix.'
Barbera is eleventh in the world championship standings with a best finish of sixth. He is yet to sign for 2012. Barbera is the Aspar team's only MotoGP rider.
Australian Damian Cudlin, who did a solid job on his MotoGP debut at Motegi - in place of Pramac Ductai's Loris Capirossi - is expected to replace Barbera.