Full-back Stephen Carr, who skippers the side when Lee Carsley is not in the starting line-up, is suspended after collecting his fifth yellow card of the campaign during the win at Stoke on Monday. Stuart Parnaby is poised to replace the former Newcastle player after recovering from injury.
McLeish insists he will treat the competition seriously but the likes of Keith Fahey, Gregory Vignal, Kevin Phillips, Carsley, Gary McSheffrey and Franck Queudrue will come under consideration for rare starts.
Number two keeper Maik Taylor, who played instead of Joe Hart in this season's Carling Cup ties, is ruled out with a back problem which has required an injection.
Birmingham (from): Hart, Doyle, Parnaby, Roger Johnson, Dann, Queudrue, Ridgewell, Vignal, Larsson, Ferguson, Bowyer, McFadden, McSheffrey, Carsley, Fahey, Jerome, Benitez, Phillips, Damien Johnson.