Birmingham have included promising midfielder Jordon Mutch in their squad for the trip to face the Lions.
Mutch impressed during a loan spell at Watford during the first half of the season and Blues want him to sign a new contract.
Midfielder Lee Bowyer will serve the second game of a three-match ban.
Millwall will be without Josh McQuoid and Alan Dunne.
Striker McQuoid this week made his loan move from Bournemouth a permanent switch but he is cup-tied after scoring a hat-trick for the Cherries against Tranmere in the first round.
Dunne serves the final game of a three-match ban following his recent red card against Leicester.
Skipper Paul Robinson is set to return to the back four having proved his fitness with a substitute appearance against Derby on Monday following a hamstring injury.
Fellow centre-half Danny Shittu has also been out with a hamstring problem and will be checked over.
Forward Shaun Batt remains a long-term absentee with a cruciate injury.
Birmingham (from): Foster, Carr, Johnson, Dann, Ridgewell, Larsson, Gardner, Ferguson, Fahey, Hleb, Jerome, Derbyshire, Taylor, Parnaby, Murphy, Phillips, Zigic, Michel, Beausejour, Jiranek.