Birmingham's key defender Scott Dann is facing a spell out of action after manager Alex McLeish confirmed he has torn a hamstring.
Dann needed a fitness test before playing in Tuesday night's Carling Cup semi-final clash at West Ham. But the former Coventry player had to be substituted at half-time of Birmingham's 2-1 first leg setback.
Now he looks certain to miss at least Sunday's derby with Aston Villa at St Andrew's and McLeish said: "We hope Scott isn't too bad but he has definitely torn a hamstring."
He added: "He passed a fitness test on the morning of the cup game.
"Sometimes players want to play through even a wee niggle.
"Sometimes they get away with it but sometimes they can end up with a bad injury."
Dann, who was playing non-league football four years ago, has formed an effective partnership with Roger Johnson since making the move from Highfield Road during the summer of 2009.
Liam Ridgewell is likely to have to switch to play alongside Johnson against his former club on Sunday with David Murphy coming into the side at left-back.
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