Newcastle Diamonds speedway rider Lewis Kerr is in an induced coma after colliding with another rider at a race in Peterborough.
The 25-year-old, from Snettisham in Norfolk, was flown to Addebrooke's Hospital in Cambridge after he crashed into a fence following the collision; the meeting was abandoned.
Team manager George English said his family are at his side.
"It was not a good looking crash and it instantly became apparent that Lewis needed major attention," he told the BBC.
"The paramedic team were superb and gave Lewis the very best of attention on the track, but also realised that it was important to get him to hospital as soon as possible."
A spokesman for the British Speedway Promotion Agency (BSPA) said: "Lewis is in a stable condition and is in the very best place for care and attention.
"There was no alternative but to abandon the meeting. All of the riders were in no state to continue after seeing what had happened.
"Our thoughts are with Lewis and his family, and we wish him a full, successful and speedy recovery.
"Our information at this stage is that he is in an induced coma and as and when any further updates are available we will issue further bulletins.
"Everyone within British Speedway sends our best wishes to Lewis and his family, and we hope for good news soon."Reuse content