The Bluebirds ground out a narrow success over Millwall on the weekend, while Blues produced another uninspiring display in the Midlands, leading to defeat at Coventry City.
After suffering back-to-back defeats for the first time since August with losses against promotion chasers West Bromwich Albion and Russell Martin's Southampton, Cardiff returned to winning ways in a gutsy manner on Saturday afternoon, beating Millwall 1-0 in a fixture devoid of genuine quality.
Erol Bulut's side struggled to create and finish clear-cut chances against their visitors from South London, and it was ultimately a corner kick which decided the destination of the points, with commanding centre-back Dimitrios Goutas rising highest to head past Matija Sarkic in the Lions' goal.
The Bluebirds' top-six push has slowed down slightly since the start of November as they have won just two of their last six Championship matches, but the Welsh outfit are seventh in the second-tier standings, behind Mike Dodds's Sunderland only on goal difference.
Cardiff have netted the fewest goals of the teams who currently occupying a top-eight position in the table, and summer arrival Ike Ugbo is the club's top goalscorer so far with just four strikes, so it is understandable why manager Bulut is interested in Kieffer Moore's situation at Bournemouth ahead of the January window.
Wednesday's hosts have already clashed with Birmingham in the opening months of this season, with the Bluebirds securing a place in the third round of the EFL Cup at St Andrew's back in late August, when a second-string side headlined by Welsh youngster Rubin Colwill won 3-1 against John Eustace's Blues.
A brilliant brace from Solihull-born Callum O'Hare sentenced Birmingham City to a 2-0 loss at the Coventry Building Society Arena against Mark Robins's Sky Blues on Friday night in front of the TV cameras and 4,000 disgruntled Bluenoses in the away end, meaning Wayne Rooney has won just one of his first nine matches in charge.
With Birmingham fielding a makeshift backline which featured midfielder Juninho Bacuna at right-back and Marc Roberts starting his first game of the term, a Coventry side who have lacked creativity since the departure of Gustavo Hamer were cutting through the Blues defence with ease at points, and the visitors were unable to muster up a serious chance of their own.
Everyone associated with Birmingham realised that the transition to "no fear" football under the stewardship of Rooney would be bumpy at the beginning, but the majority of supporters would have expected more than five points from the first nine games, and with Marti Cifuentes leading a major revival at Queens Park Rangers, Blues are now just four points above the bottom three.
Although the Manchester United and England legend is taking the brunt of the blame for recent performances, Blues' troubles away from St Andrew's were just as rife during the days of Eustace, meaning the Second City club will be looking to avoid a ninth-straight away defeat on Wednesday night, with the visitors' last victory on the road coming at Bristol City in August.
Rooney has called on his group of players to translate their positive displays on the training ground to Championship contests, with the 38-year-old urging the squad to stop relying on individual moments of magic from five-goal winger Siriki Dembele to have a chance of earning results.
Cardiff have not been the same side without the creative presence of Wales legend Aaron Ramsey, with the midfielder targeting a return to action in the New Year following a knee injury.
Callum O'Dowda was a source of attacking inspiration from the flanks last season as the Bluebirds struggled near the bottom of the division, but the Irishman is currently out due to a leg injury.
After a sluggish first-half display against Millwall, Bulut introduced former Reading forward Yakou Meite and Colwill for the second half, and the pair could be handed starting berths on Wednesday.
Birmingham are waiting for news on the seriousness of Cody Drameh's ankle injury, and with fellow right-back Ethan Laird sidelined until after January with a hip issue, Bacuna could be forced to play at full-back once again.
Dion Sanderson was stripped of his ever-present status in the second tier after he missed the Coventry loss because of a freak foot injury - it is unknown whether the Blues captain will be available for the trip to South Wales.
Academy graduate Romelle Donovan was lively off the bench at the CBS Arena, and Rooney is contemplating whether to hand the winger his full first-team debut, although the Birmingham boss is wary of throwing the 17-year-old into an unsettled and struggling side.
Krystian Bielik appeared particularly leggy against the Sky Blues last time out and might be rested for this one, meaning Croatia's Ivan Sunjic could earn his first start since the 3-1 loss at Sunderland on November 11.
Cardiff City possible starting lineup:
Runarsson; Ng, Goutas, McGuiness, Collins; Wintle, Siopis, Bowler, Colwill, Grant; Meite
Birmingham City possible starting lineup:
Ruddy; Bacuna, Sanderson, Roberts, Buchanan; James, Sunjic, Dembele, Donovan; Burke, Stanfield
We say: Cardiff City 2-1 Birmingham City
Cardiff have not been at their best in recent weeks but will be confident of recording back-to-back wins as Birmingham visit South Wales on Wednesday.
Blues have lost their last eight away matches and have shown little signs of improvement since Rooney took charge, meaning it is hard to predict anything other than a Bluebirds victory.
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