Shinya Nakano will take no further part in the Valencia World Superbike weekend after breaking his left collarbone in Saturday morning's second qualifying session.

The WSBK rookie, ninth in the championship with a best finish of fourth in the opening two rounds, was thrown from his Aprilia RSV4 after a mechanical failure.

The former MotoGP rider, eleventh in Friday's first qualifying, underwent surgery afterwards and now faces a race against time to be fit for round four of the 2009 championship, at Assen on April 24-26.

Team-mate Max Biaggi will thus be the lone Aprilia rider in Sunday's Valencia WSBK races. The Roman, fastest in Friday qualifying and Saturday free practice, was caught out in Superpole and will start just 18th.