The 22-year-old, who suffered a similar injury in Bayern's 2-0 victory over AS Roma in the UEFA Champions League last November, had to be replaced at half time following a robust challenge involving TSG 1899 Hoffenheim left-back Ermin Bicakcic.
The versatile Austrian's absence will come as a major blow to the Bundesliga leaders, who have decisive quarter-final ties coming up in both the Champions League and DFB Cup later this month. Alaba himself, meanwhile, was "really disappointed" by the news but expressed determination to come back stronger before the campaign ends. "I have one main goal: I want to be back for the finale this season. I'll make sure I recover completely and then I'll go for it in rehab.”
Bayern, who take on Klassiker adversaries Borussia Dortmund this weekend, are already without the services of Arjen Robben and Javi Martinez, while doubts remain over the fitness of Franck Ribery and Thiago Alcantara.
Bad news! @David_Alaba has suffered a medial collateral ligament tear in his left knee. 14 days in a cast and then back in around 7 weeks.— FC Bayern English (@FCBayernEN) April 1, 2015
Alaba's team-mates took straight to social media to wish the Vienna native a speedy recovery: