Having shown impressive pace from the outset, Sheridan Morais was declared unfit to start after suffering concussion in an accident at the end of Second Qualifying on Friday.
Meanwhile Kamil Krzemień, a late recruit to replace the recovering Randy Krummenacher, is also a non-starter after falling ill.
It means Frenchman Mathieu Gines will be joined on Wójcik Racing Team’s Formula EWC Yamaha by Hungarian Balint Kovacs and Swiss rider Robin Mulhauser.
Kovacs, 20, was the Polish squad’s reserve rider for this weekend, having finished last year’s 24 Heures Motos with sole riding Artur Wielebski.
Meanwhile, 30-year-old Mulhauser, a two-time FIM EWC Superstock World Cup winner, started the weekend as a reserve rider for Yamaha’s pole-setting YART team.
“It’s very sad to see Sheridan and Kamil sidelined from the race they’ve worked so hard for and had such a good chance to battle for the podium but their health takes priority,” said Team Principal Grzegorz Wójcik. “Balint raced with us in Le Mans last year. Together with Robin they’ve started this weekend as reserve riders, so they are ready for the race and we are still aiming for a strong result. Things are looking good for the 777 [Dunlop Superstock Trophy] crew, so we can’t wait for the race to start.”