The German international suffered the injury tackling Mario Gotze in Bayern’s 1-1 draw with Borussia Dortmund on Saturday at the Allianz Arena, and is expected to be out for at least five months.
The timing of the injury is even more unfortunate for the 23-year-old, as he only returned from a muscle injury 11 days ago.
“It’s a bitter blow,” coach Juup Heynckes told the official Bayern Munich website.
“The players were very shocked. He was just getting back up to speed. It’s a real choker for the lad.”
Karl-Heinz Rummenigge, the CEO of the Bavarian giants, also expressed his sympathy.
He added: “Naturally, it’s put a real dampener on our evening. He said his studs got stuck in the turf and he felt it go immediately.”
Die Roten are currently top of the Bundesliga table, eight points clear of second-placed Bayer Leverkusen, and will face BATE Borisov in the Champions League on Wednesday, having already qualified for the next stage.