Left-back Ben Thatcher suffered a partial rupture of medial knee ligaments during Sunday's derby victory over Norwich City and will miss the last two games of the season. The former Wales international was caught by a late Lee Croft challenge in the first half of Town's 3-2 win and was forced off.
Physio Matt Byard told the club site that the veteran defender could need an operation: "Ben has had a partial rupture of the medial ligaments in his left knee. He will be seeing a specialist and will obviously miss what is left of the season.
"We will see what the specialist has to say but it's possible that Ben may need surgery."
Thatcher's injury leaves the Blues short of full-backs with David Wright out for the season with a hamstring problem and Moritz Volz a doubt having had another injection for his groin injury last week.
Jaime Peters replaced Thatcher on Saturday, but is more comfortable on the right and it could be that Matt Richards makes a surprise return to the squad for the final couple of games with Dan Harding out on a half-season loan at Reading and unavailable for recall.