Bayern defender Alaba a doubt for Pokal semi-final clash with Dortmund

The Roten boss said the full-back's injury is "not such a big problem", but does not know if he will be fit to face BVB

David Alaba is a doubt for Wednesday's DFB-Pokal semi-final with Borussia Dortmund after the Bayern Munich defender was forced off with a left knee strain during their 2-2 draw with Mainz on Saturday.

Bundesliga leaders Bayern ended a bad week in which they were knocked out of the Champions League by Real Madrid with a disappointing performance, the stalemate giving RB Leipzig the chance to cut the gap at the top to six points by beating Schalke on Sunday.

The result was compounded by Alaba coming off after Arjen Robben had levelled the scores at 1-1 following Bojan Krkic's opener.

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Coach Carlo Ancelotti said after the match: "It is not such a big problem. We'll have to wait and see if he will be okay for Wednesday."

Daniel Brosinski restored Mainz's lead from the penalty spot in the 40th minute, but Thiago Alcantara levelled 17 minutes from time.

Ancelotti accepted Bayern were not at their best, adding: "We didn't play well. It was difficult for us.

"I'm confident that we will put in a very different performance against Dortmund."