The length of Schuster's absence rules him out of the crucial European clashes at Benetton Treviso and at home to the Scarlets, as well as this week's Top 14 tie against Montpellier.
Schuster, who made his French debut in November's win over Fiji, has featured in three of the four matches in the pool stages of this year's Heineken Cup.
Perpignan currently sit third in Pool 5 behind former champions Leicester Tigers and leaders the Scarlets but two victories in their final two group matches would give them a great chance of reaching the knockout stages.
Quarter-final qualification is an aim the Catalan giants have achieved only once since they were beaten in the 2003 Heineken Cup Final by Toulouse but last month's home victory and away draw with Leicester has greatly increased their chances of making amends this time around.
While Schuster's absence is an unwanted distraction for Perpignan, the club did receive one piece of positive injury news this week.
Cameroon international second row Robins Tchale-Watchou will be fit to play again in 10 days having entered the final stages of his rehabilitation following a wrist injury.
The 27-year-old former Stade Francais player has featured in all four of Perpignan's Heineken Cup matches so far this season, having played in five of the six group matches last year.