The German Football Association (DFB) have confirmed they are reviewing video evidence of an incident in Hannover's 1-0 win over Nurnberg on Friday, in which defender Emanuel Pogatetz is alleged to have punched opponent Philipp Wollscheid.
Since the referee did not award a foul, the DFB are permitted to take retrospective action against the Austrian, should the video footage prove conclusive.
Furthermore, both Pogatetz and Wollscheid have been asked to provide their version of events before the DFB's disciplinary panel decides what action, if any, to take.
Should Pogatetz be found guilty of violent conduct, he would face at least a three-game suspension.
That would leave Hannover short of defenders for their clashes with Hertha Berlin and Mainz, since Karim Haggui is on international duty at the African Nations Cup.