West Ham are without midfielder Victor Obinna, who completes a three-match ban after his red card in the first leg.
Frederic Piquionne is also suspended following his controversial dismissal for celebrating with fans after scoring against Everton at the weekend.
MATCH PREVIEW Bottom of the Premier League they may be, but West Ham are a different proposition in cup competitions this season. Their 2-1 win over Birmingham in the first leg at Upton Park was their sixth straight victory in cup competitions - two more than they have managed in the Premier League.
West Ham manager Avram Grant took Portsmouth to the FA Cup final last season. If he books another Wembley trip on Wednesday it will provide welcome relief from the intense media speculation about his future.
We have a bunch of players who will bounce back well. It's a huge opportunity for us Birmingham manager Alex McLeish after the 5-0 defeat at Manchester United Alex McLeish's Birmingham stand in their way. Like the Hammers, they are struggling in the Premier League and Saturday's 5-0 drubbing by Manchester United left them only one place and one point above the relegation zone.
Trailing 2-1 from the first leg, they must put their league form behind them and conjure up a win at St Andrews, something they have not managed since their quarter-final victory over Aston Villa on 1 December.
MATCH FACTS Head-to-head
• This is the 91st competitive meeting of these clubs. Birmingham lead by 38 wins to 31, with 20 draws.
• West Ham have lost only one of their last nine games against Birmingham, winning five of those matches.
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• Birmingham's 1963 League Cup triumph is the only major trophy in the club's history.
• The closest they have come to winning more silverware ended in disappointment when a Liverpool side managed by Gerard Houllier beat them on penalties in 2001.
• They are playing in the semi-finals for the fifth time, and their first in 10 years since finishing runners-up in 2001.
• Their two semi-final losses were in 1967 and 1996. Their overall semi-final record is W2, D1, L6.
• The 1966 and 1981 runners-up are making an eighth appearance in the semi-finals, and their first since 1989/90.
• They have lost five of their previous seven semi-final ties.
• Their overall semi-final record is P17 W7 D2 L8 (including two replays in 1972).
• The Hammers have won six out of six matches in cup competitions this season.
Gardner: 5 goals (1 in League Cup); Zigic: 4 goals (2 in League Cup); Ridgewell: 4 goals (1 in League Cup), Jerome: 4 goals (0 in League Cup)
Piquionne: 8 goals (1 in League Cup); Cole: 6 goals (3 in League Cup); Parker: 6 goals (2 in League Cup)
MATCH OFFICIALS Referee: Howard Webb
Assistant referees: Dave Bryan & Jake Collin
Fourth official: Lee Mason