Saracens and former All-Black lock Chris Jack will be sidelined for six to eight weeks due to knee ligament damage.
The former New Zealand Player of the Year sustained his latest injury during the European Challenge Cup clash with Viadana last weekend and now looks set to miss Rounds 3 and 4 of the Saracens European Challenge Cup campaign.
Jack joined Saracens following his World Cup campaign with New Zealand and in his first season with the "Men in Black" helped the Watford based club qualify for the Heineken Cup quarters-final for the first time scoring two tries in five European appearances.
A hand injury ruled him out of Saracens quarter-final with the Ospreys and semi-final clash with Munster.
Saracens are currently top of the Pool 5 and will face Bayonne in Round 3 on Saturday, 6 December at 8.45pm (local time), with the game being broadcast live on Eurosport France and Sky Sports.
Finals Edition: Listen to the best guide to the European Rugby Cup Finals weekend in Dublin, which sees Leinster Rugby take on Stade Francais Paris at the RDS on Friday night in the Amlin Challenge Cup Final and then ASM Clermont Auvergne tackle Toulon in an all-French affair at the Aviva Stadium on Saturday.