MotoGP world champion Valentino Rossi will undergo surgery on his lingering shoulder injury, after the end of the 2010 racing season.

The 31-year-old Italian damaged ligaments in a motocross accident in April, although it was initially claimed he had suffered only bruising and the incident was even labelled by some as a non-story.

Instead, the shoulder has proven even more troublesome to heal than Rossi's broken leg, sustained at round four in Mugello, and he feels he has no choice but to undergo surgery in order to be fully fit for 2011.

"In the end the problem is the shoulder. At the end of the year I'll have it operated on," Rossi told Sky Italia TV.

Exactly when Rossi will have the operation is less clear.

Rossi will naturally try to fit the surgery and rehabilitation into a space in the winter testing schedule, but with no confirmation that he will be allowed by Yamaha to test the Ducati before the end of 2010 Rossi might have more time on his hands than he had hoped for.

Rossi has not won a MotoGP race since round one in Qatar, just before he injured his shoulder.