Billy Clarke has been ruled out for the remainder of Charlton’s season with a knee injury.

Clarke, a summer signing from Bradford, was forced off in the 2-0 defeat to Blackburn on Saturday.

He is set to undergo surgery which will be followed by an eight-month rehabilitation period.

Charlton head of medical services Alastair Thrus said: “Unfortunately, Billy won’t play again this season and everyone is really gutted for him.

“He’ll have surgery in the coming weeks, once the knee has settled down, and after that he will have around an eight-month period of rehabilitation before he can return to play.

“We’re hopeful that he could be back for the start of next season.

“This is one of the toughest injuries for a player to accept but Billy has been through it before.

“He suffered the same injury to his other knee in 2010, so he knows what to expect from his rehabilitation and he will be seeing the same specialist now as he did then.”

There is more bad injury news for Charlton as Jake Forster-Caskey picked up a quad injury and won’t play again this year.

Meanwhile, crocked duo Ahmed Kashi and Patrick Bauer are targeting the New Year’s Day fixture against Gillingham.

A thigh strain means Tariqe Fosu is not expected to return to action for another four weeks, while long-term absentee Lewis Page could train in six weeks’ time after picking up an achilles problem.

But Ricky Holmes could be fit for the Boxing Day clash with Southend to ease the Addicks’ ever-growing injury list.