Millwall expect new signing Shaun Batt to miss the entire season after undergoing surgery on his knee.
Batt made his move from Peterborough permanent last month after spending part of the 2009/10 campaign on loan with the Lions and helping them win promotion.
However, he sustained a serious injury in a friendly against AFC Wimbledon a fortnight ago and will not play any part in the Championship this term.
Physio Bobby Bacic said: "Shaun underwent surgery on Thursday night to his knee and the surgeon invited me to watch the operation.
"His anterior cruciate ligament has been reconstructed and part of his hamstring had detached.
"The surgeon was happy with the procedure but we do not expect Shaun to play this season as recovery from this procedure usually takes at least nine months."