Steven Caldwell's season has been brought to an abrupt halt and he will play no further part in Birmingham's promotion push.
The Scottish centre-half was forced off during the first half of the Blues' 1-1 draw with Ipswich on Tuesday.
A hamstring problem saw his night cut short and it has now been confirmed that he will sit out the remainder of the 2011/12 campaign.
Caldwell has been an influential figure for Birmingham this season and has filled in as skipper during Stephen Carr's absence through injury.
He joins a growing list of senior stars currently spending time on the treatment table at St Andrews - with first-choice goalkeeper Boaz Myhill as well as midfielders Guirane N'Daw, Keith Fahey and Jordon Mutch recently sidelined, along with Carr and Jonathan Spector.
Manager Chris Hughton will now be forced to shuffle his pack as he attempts to guide Birmingham through the Championship play-offs and back to the Premier League at the first time of asking.