Toulon will be without Bakkies Botha for up to two months after he suffered a fractured eye socket during Sunday's 62-0 rout of Sale.
The South African international was forced off just before half-time in the Heineken Cup clash and will undergo surgery later this week.
Botha, who has won 76 caps for the Springboks, only recently extended his contract with the Top 14 leaders until 2015.
The 33-year-old second row started 10 of 12 domestic matches this season and featured in all four of their Heineken Cup victories, which puts them in with a great chance of securing a home quarter-final.
Half-backs Frederic Michalak and Sebastien Tillous-Borde also picked up knocks against Sale, but they should be fit to face Top 14 strugglers Agen on Saturday.