Mark Hudson v Clayton Donaldson
He was absent for David Wagner's 2-0 triumph at St Andrew's last December but Clayton Donaldson is now fit - and unfortunately for Town, he's firing.
The striker has 11 goals this season, but four have come in his last four appearances, and he netted a brace in his last outing against Preston.
Unsurprisingly for a man who leads the line in Gary Rowett's 4-2-3-1 formation, he's the club's top scorer, but he's also top of the assists chart with seven to his name.
Keeping him quiet will be key to keeping a clean sheet, so step forward Mark Hudson.
The skipper had a good game against the direct style of Rotherham on Tuesday and more of the same is required.
Birmingham have scored in each of their last seven games - the last time they failed was in a stalemate with Wolves on 13 March and their record in Huddersfield is far better than Town fans are comfortable with. Time for change.
Nahki Wells v Michael Morrison
Town's star man is one of the main contenders to be crowned Town's Player of the Year next weekend. He has 18 goals to his name so far and has three games left to hit his target of 20.
Goals against Blackburn and Rotherham directly contributed to Town picking up four points on the road in their last two games, and now he'll want to turn it on in front of the home faithful. He last scored at the John Smith's Stadium against Reading on 8 March, although Burnley, Sheffield Wednesday and Hull City have been the visitors since.
He single-handedly changed the game on Tuesday by conjuring a goal out of nothing and his value to Town just keeps soaring in an upward trajectory.
Up against him will be the physical prowess of Michael Morrison, an old favourite of Chris Powell's at Charlton.
Virtually ever present, he's played the most minutes of anyone at Birmingham this season and is a presence in both penalty areas - as three goals and two assists will attest.
Can Nahki provide the invention to get past?
Jamie Paterson v Stephen Gleeson
The loan signing of Jamie Paterson has been key to Town's season, and every effort should be made to retain his services next term.
Working his magic from the no.10 role, the Nottingham Forest loanee's creative football brain has been essential in unlocking packed defences, and given Town the option to attack through the middle as well as down the wings.
His absence against Blackburn through injury was noticeable in what was a scrappy encounter missing some added guile, and his return from the bench against Rotherham was a welcome sight.
Stephen Gleeson has been a mainstay for Rowett and his partnership with Maikel Kieftenbeld, marshalling the midfield engine room, is designed to protect the defence and give the attackers freedom to move forward. David Wagner would thoroughly approve.
But with Kieftenbeld facing a late fitness test, the onus will be on Gleeson to keep close tabs on the roaming feet of Paterson. If he can cut off the supply line, Nahki Wells' ability to cause damage will be drastically reduced.