Langerak, 22, has been a regular in Dortmund's matchday squads all season as the team's back-up goalkeeper but could be set for his debut in a crucial league game at Bayern's Allianz Arena on Saturday.

Weidenfeller hobbled out of Dortmund training on Tuesday, after a collision with defender Mats Hummels left him writhing in pain with an injured knee.

The severity of Weidenfeller's injury isn't known at this stage although it has been speculated it could be a torn ligament after thick swelling on the knee, according to Der Westen.

The Dortmund number one will undergo analysis on the knee by team physician Dr Markus Braun on Wednesday morning (German time) to ascertain the extent of the injury.

Ex-Melbourne Victory shot-stopper Langerak hasn't played a minute of competitive first-team action for BVB, but last week put in a full 90 minutes for Dortmund's II side in a 1-0 win over Moenchengladbach II in Regionalliga West.

Dortmund currently lead the Bundesliga by 10 points from second-placed Leverkusen, while Bayern are a further three points behind in third with 11 matches left in the season.