Bayern Munich will be without versatile left-back David Alaba for the closing stages of the season after he was ruled out for around seven weeks with a torn knee ligament. Alaba, out for three months earlier this season after a partial ligament tear in his right knee, was injured while playing for Austria in their 1-1 draw against Bosnia on Tuesday. 'I am bitterly disappointed,' the 22-year-old told the club's website. 'But I have a big aim and that is to be there at the season finale.' David Alaba is tackled by Emir Spahic's tackle during Austria's 1-1 draw against Bosnia-Herzegovina . Marc Janko (left) celebrates with Martin Harnik and Alaba after he scored against Liechtenstein last Friday . He is set to start rehabilitation work in about a month, Bayern said. Alaba had been in superb form for Bayern since his comeback, helping them stay firmly on track for a treble of titles with some spectacular goals. Bayern, who are top of the Bundesliga with eight games left and through to the German Cup last eight, face Porto in the Champions League quarter-finals later this month. Alaba (left) has been in excellent form for Bayern this season as the Bavarian giants chase a treble of titles .
Austria drew 1-1 against Bosnia-Herzegovina on Tuesday night . David Alaba picked up a knee injury during the first half of the game . Alaba was out for three months earlier this season after he suffered a partial ligament tear in his right knee .