Birmingham City defender Scott Dann is out of Sunday's big derby with Aston Villa with a hamstring injury, manager Alex McLeish has confirmed.
The centre-back had to be substituted at half-time of Tuesday's Carling Cup semi-final first leg defeat to West Ham United and is now facing a spell out of action.
The former Coventry City stopper had needed a fitness test prior to the Upton Park clash and McLeish has revealed the gamble on the 23-year-old has backfired significantly.
The Blues boss said: "We hope Scott isn't too bad but he has definitely torn a hamstring.
"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 a formidable partnership with Roger Johnson since making the move from the Ricoh Arena during the summer of 2009.
In his absence, Liam Ridgewell is likely to play alongside Johnson against his former club, with David Murphy coming into the side at left-back.
Depending on how severe the tear is, Birmingham could be without Dann's services for forthcoming games against Manchester United and Manchester City, as well as the second leg of their clash with West Ham.