Millwall captain Tony Craig is likely to miss the rest of the season after having surgery on a knee injury.
The 30-year-old defender sustained ligament damage in his left knee during the 0-0 draw with Bradford City on Saturday, 31 October.
"Tony will remain on crutches and in a brace for six weeks to begin with. His is classed as a long-term injury," said Millwall physio Bobby Bacic.
"If Tony returns before the end of the season we will regard this as a bonus."
Craig re-joined Millwall this summer after leaving Leyton Orient and has made 19 appearances during his third permanent spell at The Den.