Phil Neumann, a center-back for Hannover, has already had a physical, according to sources who spoke to Football Insider.
The League One team is in negotiations to sign the 27-year-old after their £3.4 million offer was turned down last summer.
Although Birmingham hopes to finalize a deal before the January window closes, negotiations between the clubs have stalled, with Hannover demanding an asking price of £4 million.
Neumann is thought to have arrived in the UK last Friday and undergone a medical at Birmingham.
Neumann’s accomplishments in the German second division have made him a major target for the Blues.
He missed the match against Hertha Berlin last month due to suspension, but he has played 90 minutes in all but one of Hannover’s games this season.
The former Germany Under-20 player has 173 games in the 2.Bundesliga during stints with Hannover, Holsten Kiel, and Ingolstadt, making him an accomplished operator at the division level.
Although he can play right-back, his primary position is center-back.
With two games remaining against its nearest opponents, Birmingham leads League One under manager Chris Davies, two points clear of Wycombe and Wrexham.
In order to acquire striker Jay Stansfield as the largest of 17 agreements, the Blues broke their transfer record during the summer transfer window.
