Toulon's South African scrum-half Michael Claassens has been ruled out for six weeks with a hand injury.
Claassens was forced off in Toulon's 51-28 win over Glasgow in the opening round of the Heineken Cup on Sunday.
The former Bath number nine broke a bone in his left hand, forcing him out for the next month and a half.
Toulon also lost fly-half Jonny Wilkinson to a cut on his hand, but after stitches he is expected to play against Cardiff Blues next weekend.
The European champions moved Frederic Michalak to scrum-half in the wake of Claassens' injury, but also have Sebastian Tillous-Borde in their squad with Michalak to cover.
Toulon's other number nine, Nicolas Durand, is currently on-loan at Perpignan.