Millwall defender Tony Craig will miss the remainder of the season after suffering an ankle injury in the 1-0 defeat to Huddersfield.
Craig suffered the knock during the match, yet carried on playing, and scans have revealed that he will be out for six to eight weeks.
This means the Millwall trainee, who has had spells at Crystal Palace and Wycombe, will also miss the play-offs if the Lions do not achieve automatic promotion.
However, there is better news for Alan Dunne and Andy Frampton, who could be fit to face Leyton Orient on Saturday after recovering from groin and calf injuries respectively.
Meanwhile, Millwall have been fined £2,500 by the Football Association for failing to control their players in the 1-0 defeat to Wycombe on 20th February.
The Lions pleaded guilty under FA rule E20 after several players were involved following an incident between Tony Craig and Chairboys midfielder Gareth Ainsworth during the game at Adams Park.
Millwall chief executive officer Andy Ambler told the club's official website: "We admitted to the charge, but I felt the FA took into account the mitigating circumstances when imposing the level of punishment on us.
"We do our level best to ensure our players conduct themselves correctly on the field, and the manager has reminded them of their responsibilities."