Plymouth Devils rider Justin Sedgman has returned to his native Australia and will not ride for the club again this season.
It means the club will operate a rider replacement for him for the rest of the campaign, starting with Rye House's Ritchie Hawkins for Friday's match against second-placed Sheffield.
"Hawkins is the ideal choice as guest," said promoter Mike Bowden.
"He has a positive attitude and rides well at our track."
The club also have a guest in place of the injured Kyle Hughes as they look to try and get off the bottom of the Premier League.