Mark Webber was lucky to escape more serious injury when he collided with a car head-on whilst riding a bicycle during his Pure Tasmania Challenge, it has been revealed - as the very future of the 250km mountain biking, kayaking and trekking endurance event possibly hangs in the balance.

The Australian hit the car during a mountain-biking descent on a remote road near the state capital of Hobart on Saturday morning, and has since undergone surgery on a badly broken right leg that is likely to see him forced to miss the bulk if not all of pre-season testing for the 2009 Formula 1 World Championship - one in which the cars will run to significantly different regulations than in recent years, making preparation more important than ever.

Whilst Webber is expected to be back on-track in time for the curtain-raising Australian Grand Prix in front of his home fans on 29 March [see separate story - click here], his future contractual freedom to participate in the outdoor adventure Pure Tasmania Challenge is likely to be the subject of some discussion with employers Red Bull Racing, the energy drinks brand's close association with extreme sports notwithstanding.

"It would be a stretch to say the event was in any kind of threat from that perspective," urged Geoff Donohue, director of the 2008 edition and also involved with the 32-year-old's management team, in an interview with Sydney newspaper the Daily Telegraph.

"Having said that, Mark is very loyal to his employer so I'm sure all of that will be discussed. If you look at other Formula 1 drivers you will find they all do a variety of training that has risk."

Webber's father Alan, meanwhile - one of the first to reach the scene when the accident occurred - told British newspaper The Times that his son had been fortunate not to be much more seriously hurt. The New South Wales native was initially reported to have sustained 'serious but not life-threatening injuries'.

"It was messy," Webber Snr said of the compound fracture of the tibia and fibula. "Mark will have to stay in the hospital here for another four or five days.

"It's a question of whether he recuperates in Melbourne or comes up to our house in Queanbeyan, where he could use the Australian Institute of Sport to help aid his rehabilitation."