Shane Byrne and Noriyuki Haga will be notable absentees from the grid at Cadwell Park after both riders were eliminated by shoulder injuries sustained in crashes during free practice.
Byrne, who has already reached the forthcoming Title Showdown, came down heavily during FP2 and was taken to hospital with shoulder pain.
Following scans, Rapid Solicitors Kawasaki rider Byrne has been confirmed with ligament damage in the shoulder, an injury that could require surgery that would potentially put him out of action for the coming Donington Park round too.
Joining him on the Cadwell Park sidelines will be Haga, who fell heavily at Mansfield during FP3. Taken to the medical centre for checks, Haga is also being treated for ligament damage in his shoulder and will take no further part in this weekend's event.
The injury is a potentially critical blow to his hopes of reaching the Title Showdown, the Japanese rider currently sixth in the standings with a slender seven point advantage over Ian Lowry.
Just the Cadwell Park and Donington Park rounds remain before the three-round Title Showdown gets underway at Assen on 23rd September.