Sheffield will know today the full extent of Andre Compton’s injury - with his season hanging in the balance.
Compton is seeing a specialist after crashing at Edinburgh last Friday and suffering a suspected broken wrist.
If he requires surgery, it will mean his season ends early for a second successive year through injury.
Club bosses are hoping for some good news.
Co-promoter Damien Bates said: “We’re desperately hoping it’s good news because we can’t keep having this misfortune.
“Just as you bring a rider in, then you lose another. I’m hoping it will be only short- term, but I have to say the early suggestions aren’t good.
“You have to feel for Andre because I think he’s done a great job for us this season; ,it’s not been easy with all our problems but so far we’ve been able to keep the season going.
“It’s been a nightmare, to be honest, and it’s kept me busy trying to book the right guest, but our crowds have been good and we’ve kept enjoying our speedway.”
Tigers have booked Owlerton specialist Brady Kurtz for this Thursday when they face Glasgow in their League Cup semi-final.
Said Bates: “Brady is very happy at Somerset, but he admits he loves riding the Sheffield track. You can see every time he goes out there, he relishes the prospect. I’m happier having him riding for us than against us for sure. I’d like to thank Brady and Somerset for agreeing to help us out once again.”