Wolverhampton and Plymouth star Ty Proctor will miss the rest of the season because of injury.
Proctor suffered nerve and muscle damage to his neck and back following a crash at Edinburgh in May and he needs surgery to fix the problems.
Wolves promoter Chris Van Straaten said: "Obviously this is extremely bad news both for Ty and for the club.
"The priority now is for Ty to get himself right. It's likely to be a six-month recovery process for him and the surgery is a delicate process.
"It's cruel for Ty because he's been riding superbly. He had shown the kind of form we spotted in his potential when we first brought him to the club.
"We can only wish him well in his recovery with his top priority to be back racing for the start of the 2014 season.
"As a club we must now look at our options. Peter Adams (team manager) and myself will have a chat about things and we have no meeting next week because of the Speedway World Cup so we have some breathing space."