Charlton loanee Jonathan Leko faces a long absence after damaging his anterior cruciate ligament, and has gone back to parent club West Brom.
Forward Leko, 20, returned to Albion to begin treatment having scored five goals in 21 games during a loan spell which was meant to last all season.
He suffered the injury only 11 minutes into the Addicks' 2-2 Championship draw at QPR on Saturday.
"Jonathan is out for the rest of the season," Charlton boss Lee Bowyer said.
"It came from nothing - he jumped, landed, jolted his knee a bit and has done his ACL.
"He'll be out for the rest of the season, going into next season as well."