It was in the fourteenth heat of the Polish league match between GKM Grudziadz and Chris Holders Unia Leszno that the accident occurred.
Holder was hit by Polish junior Kacper Pludra, which ended in Holder landing his back against the part of the fence that lacked inflatable protection.
Västervik's team leader Morgan Andersson is furious about the incident that caused the injury.
– We are of course saddened by the injury news, especially how it happened. It's an assassination attempt," Andersson told SVT Sport.
Can you elaborate on what you mean by attempted murder?
"He was definitely looking to catch Chris and I'm really just happy that Chris was so aware that he was able to get off the bike in time.
Fracture of a cervical vertebra
The 35-year-old Australian landed hard, but made it off the runway on his own machine. After the game, Holder was taken to hospital where he was examined.
The X-rays now show that he has suffered a fracture of a cervical vertebra that can keep him out for 8-10 weeks, Unia Leszno announces via social media.
"The message that Chris' Polish club is going out with is not definitive. Chris is currently in England for a second opinion and it is really only then that we will know more for sure, says Andersson.
The announcement means that the world champion from 2012 could be absent for half of the Swedish season, which is a tough blow for Västervik who signed Holder for this year's season.
"Of course, it's not optimal at all. We are working on finding a replacement and it remains to be seen what it ends up in.
Västervik starts the speedway league on May 2 at home against the Lions.
SVT Sport has reached out to GKM Grudziadz for a comment without success.