Ian Hutchinson is in hospital with a compound fracture to his left leg after a first lap crash while racing at Silverstone.
He came off in wet conditions on the first corner of the British Supersport Championship race and was then hit by a following machine.
The Bingley Bullet, who made history by winning all five solo races at TT 2010, was treated by medics at the track before being air-lifted to hospital.
It was later confirmed he had suffered a compound fracture to the tibia and fibula in his lower left leg.
Boxing: November fight date confirmed for Sam Rennie
Cricket: Lucy Barnett named August ICC Women's Player of the Month
Shooting: Kirkpatrick takes the win by one
Powerlifting: Isle of Man to begin Commonwealth championships campaign