Birmingham defender Scott Dann has been ruled out for the rest of the season with the hamstring injury suffered in the Carling Cup tie at West Ham United last week.
Dann has undergone surgery on the injury, which may force Blues into the transfer market to replace one of the most important players in their team.
Blues boss Alex McLeish said: "Scott had a successful operation the other day but he will be out for the rest of the season. You don't want to see your back four being disrupted too much. Scott has been an excellent performer, very consistent, and he is going to get even better.
"But I'm philosophical about these things. You've just got to get on with it. Managers can't legislate for injuries and suspensions and we've lost a good man. But it is up to his team-mates to show we won't miss him as much as we think.
"We've got Martin Jiranek here as cover. Martin, although he is untried in the Premier League, is an experienced international."
Dann has started 20 Premier League games this season, scoring two goals.