Bath forward Lewis Moody will be out of action for 12 weeks after having surgery on a shoulder injury.
The former England captain, who retired from international rugby in October, has made just 13 appearances for Bath since his arrival last year.
Bath have received an injury boost with Francois Louw and Stephen Donald both expected to be fit to face Leinster in the Heineken Cup on Sunday.
The West country side are second to Leinster in Pool Three after two games.
Coach Brad Davis told BBC Radio Bristol: "We'll have Francois Louw back this week, and Stephen Donald, who if he gets through this week in training, will be available for selection.
"These two guys coming back is a big bonus for us but unfortunately Lewis is going to be out for 12 weeks and, with the other long-term absentees, we are fighting a battle.
"You've just got to crack on and deal with it. I'm pleased that we've got a couple of other players back and I'm looking forward to the day we have everyone back so we can select from a fully fit squad.
"I'm just gutted for the player himself. He came back enthusiastic in training but I'm sure he's going to give loads off the field now to keep himself occupied. It's disappointing but what can you do? He's always played the game that way, he's always going to pick up knocks."