South African wing Wandile Mjekevu, French lock Romain Taofifenua and centre David Marty, Georgian prop Giorgi Jgenti and ex-England No8 Luke Narraway all require treatment following the 30-23 defeat to last season's beaten Heineken Cup finalists.
Mjekevu, Taofifenua and Jgenti will all be absent for both games in the December double header, while Marty and Narraway will definitely miss at least the away tie this Sunday.
Mjekevu, who scored a stunning solo try in the Round 2 win over Edinburgh, has a sprained ankle and will be out for three weeks; Taofifenua will be absent for the same length of time with a twisted knee; and Jgenti won't feature for six weeks and could therefore also be forced to sit out the final two rounds in January as a result of a fractured wrist.
Marty is struggling with a calf injury and Narraway a hip problem but both former internationals should be available for the return leg with Munster at the Stade Aime Giral on Saturday, December 14.
The news comes on the back of the suspensions of centre Lifeimi Mafi and prop Sona Taumalolo, with the former serving a six-week ban for a tip tackle on Gloucester's Ryan Mills in the opening round of European action and the latter unavailable for four weeks after his dismissal for punching in Tonga's autumn Test defeat to France just over a fortnight ago.
Perpignan currently top Pool 6 after their maximum-point win over Edinburgh followed a losing bonus point at Gloucester but the pool is incredibly evenly matched after all four sides won one and lost one of their first two fixtures.