Chris Jack will miss Sararcens rematch with high flying Ospreys after suffering a hand injury in the EDF Energy cup semi-final defeat last weekend to Lyn Jones' side.
The 29-year-old All Black fell heavily in the match and sustained damaged tendons and as a result he has already undergone surgery in the 30-3 defeat in Cardiff.
Jack has been instrumental in helping Saracens to their first Heineken Cup quarter-final appearance and Saracens Director of Rugby Alan Gaffney admitted the giant second row would be missed by his side.
"It's a blow for the club," he said. "Chris has made a great impact since he arrived at the club and I know that he will still play an active role in supporting the guys.
But Gaffney says the very presence of "Even though he won't be able to get out on the pitch, with his knowledge and experience he still has a very important role to play for us."
Jack played in three of Saracens' Pool 5 matches, and scored two tries in the round 5 demolition of former finalists Biarritz OIympique in a Heineken man of the match performance.
