Birmingham City will assess Christoph Klarer’s injury before Charlton after the Austrian centre-back had to be replaced in the 4-0 victory over Cambridge United on Tuesday.

Klarer was replaced by Grant Hanley in the 71st minute after signalling to the bench that he was unable to continue. The 24-year-old, who has been wearing the captain’s armband of late with Krystian Bielik on the bench, appeared to be suffering discomfort in his lower back.

“He was feeling something, the extent of it I don’t know, but he couldn’t continue so it’s a bit of a concern,” Blues manager Chris Davies said afterwards. “We’ll have to see how he is in the next couple of days.”

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In-form Charlton visit St Andrew’s @ Knighthead Park having won five of their last six games to climb up to fifth in League One. The Addicks are one of two sides to defeat Blues in the league this season.

Whilst Klarer is a doubt, Scottish midfielder Marc Leonard won’t play any part after suffering a nasty gash to his knee in Saturday’s FA Cup defeat to Newcastle. Blues expect to be without Leonard for a while but Taylor Gardner-Hickman and Emil Hansson are progressing.

Davies added: “Marc Leonard had treatment at the hospital and has now come out, I can’t give anything definitive but we’re hoping there’s nothing significant or structurally wrong with his knee. It’s a really deep gash so it’s a case of that recovering and they usually take a good few weeks.

“Taylor is getting closer day by day, but he’s still a little bit away. Emil Hansson is training now, hopefully next week he’ll be in full training.”