Stoner: Wrist operation or career over.

2007 MotoGP world champion Casey Stoner has confirmed that he will undergo a wrist operation at the end of this season - and revealed that 'it could be our career over' if he didn't.

At Misano in late August, Stoner discovered that a broken scaphoid bone in his left wrist, originally damaged in 2003, had never healed properly. The Ducati star has continued to ride, claiming the pain isn't a problem, but is increasingly concerned about a lack of strength.

"Pain wise it's fine, it's just a weakness in change of direction and things like that," said Stoner, speaking on the eve of his home Australian Grand Prix weekend. "I'm a little bit worried about this weekend, to see how many laps we can do in the race before we start getting tired. If we feel comfortable and the bike is working well that should make things easier. So we're going to have to work really hard this weekend to set the bike up as best we can.

"I've opted to take the strapping off basically because it was just too much of a hindrance. I couldn't pick the bike up well enough and couldn't grip the handlebars when I was picking the bike up. So it's a lot easier to ride in some ways, without the strapping."

Three races remain until the end of the 2008 season, at Valencia on October 26, after which Stoner has no choice but to undergo an operation - ruling him out of the post-season 2008 test sessions.

"We have to have an operation; if we don't it could be our career over," he declared. "It's disappointing, five years after getting an operation done, it starts to flare up now. But in some ways we're lucky it did show us what the real problem was, so we weren't just ignoring it and finding a bigger problem later on.

"It's better for us to get it fixed at the end of this season. It'll take about three months to come good, but we should have that amount of time before testing starts next year and then we should be a little bit more competitive."

Stoner took a memorable home victory at Phillip Island last season and Ducati MotoGP project director expects Stoner to 'fight like a lion' despite his diminished physical condition.

"Philip Island is traditionally a favourable circuit for our bike and we've had good results there," he began. "I'm sure Casey will be fighting like a lion once again even though he's not in the best physical shape and Marco [Melandri] should also be able to be able to put in a good performance on a circuit that will suit the characteristics of his Desmosedici."

Stoner will start this weekend's event second in the world championship standings, but just 11 points ahead of Honda's Dani Pedrosa.