Stephen Thompson is recovering from a broken vertebrae in the Royal Victoria Hospital in Belfast after crashing at the Ulster Grand Prix on Saturday.
Thompson was competing in the Supertwins race when he came off on the approach to Ireland's Corner.
The 36-year-old has damaged some other vertabrae and surgeons are deciding whether to operate on the injury, pin it or let it heal naturally.
Doctors are confident the injury will not result in serious long-term damage.
Thompson is expected to wear a body cast for a few months while the injury heals.
The Crumlin rider is a regular competitor at the North West 200, Isle of Man TT, Ulster Grand Prix, and Macau Grand Prix road circuits, and also takes in a number of short circuit events.
He finished in sixth position in last week's Dundrod 150 Superbike race and produced some fast laps in qualifying.
Saturday's race programme was marred by a number of incidents, but none of the riders involved are thought to be seriously injured.
English rider Lee Vernon died on Friday from injuries he received in a crash at the Dundrod 150 meeting on Thursday.