Somerset Rebels' Christian Hefenbrock has been ruled out for the rest of the Premier League season after breaking his leg.
The German international fell awkwardly during heat eight of their defeat by Scunthorpe on Sunday.
After receiving on-track treatment he was transferred to hospital where it was confirmed he had broken his tibia and fibula.
"This is a cruel blow for Christian," said Rebels team manager Steve Bishop.
"Obviously the thoughts of everyone associated with the Rebels are with Christian as we wish him a speedy recovery."
Somerset will use the rider replacement facility to cover for Hefenbrock's absence, with Cory Gathercole, Dakota North, Alex Davies and James Holder eligible to take over his rides.