German time trial world champion Tony Martin has fractured his cheekbone after a training accident on Wednesday, according to his Omega Pharma-QuickStep team.

A car was involved in the incident near his home in Switzerland, which resulted in Martin losing consciousness. He was taken to hospital in Munsterlingen where X-rays revealed fractures to his cheekbone and jaw. The injury may require surgery.

Martin, 26, switched to the Omega Pharma-QuickStep team for 2012 after the demise of his former squad, HTC-Highroad. Last year he won stages of the Tour de France, Vuelta a Espana and Criterium du Dauphine, as well as overall wins in Paris-Nice, Volta ao Algarve and Tour of Beijing alongside his world time trial title.

Martin had been scheduled to take part in the 2012 Tour de Romandie over April 24-29, but his participation in the race has now been placed in serious doubt.

Martin’s American team-mate Levi Leipheimer is also currently sidelined after being hit by a car. Leipheimer suffered a leg fracture as a result of the collision on April 1 in Bilbao, Spain.