Pedretti suffered the injury in Game 5 of the ZSC Lions' quarterfinal series against Lausanne HC. They will have to make do without their 29-year-old forward for the remainder of the season.
Swedish forward Marcus Krüger and Finnish forward Teemu Rautiainen are both considered day-to-day with upper-body injuries. Krüger, for his part, crashed head-first into the goal bar after he got hit by LHC's Aurélien Marti in Game 5.
The ZSC Lions will start their semifinal series against Genève-Servette HC on Sunday at the Hallenstadion.