Neil Harris does not know how long Fred Onyedinma will be out for after missing their 2-0 win over Birmingham on Saturday.
Blues defender Maxime Colin diverted Steve Morison’s pass into his own net in the 47th minute before Ryan Tunnicliffe’s first Lions goal put the game to bed.
But Millwall forward Onyedinma, 20, joins Shaun Williams and Byron Webster on the sidelines after pulling out of training earlier in the week.
Den boss Harris said: “Fred has carried a knock for a couple of weeks.
MORE: Player ratings from Millwall’s win over Birmingham
“He pulled out of training yesterday which is a blow because he brings us another option.
“He gives us another attacking threat with his pace and strength.
“He’s been really impressive with his starting performances and off the bench so it was a real blow to lose him. We don't know how long he’ll be out for.”
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here