Germany defender Lukas Klostermann needs knee surgery, Bundesliga leaders RB Leipzig said Tuesday.
The 24-year-old defender will undergo keyhole surgery on his left knee on Wednesday to determine how long he will be out for.
Klostermann went down in Saturday's 2-0 away win at Augsburg, which kept Leipzig top of the German league after four games.
The injury rules him out of Tuesday's Champions League home match against Turkish side Basaksehir.
Leipzig's mobile centre-back played out of position in Germany's most recent internationals this month.
He set up Leon Goretzka's winning header from the right wing in a 2-1 away win against Ukraine in the Nations League, then switched to right-back for the 3-3 draw with Switzerland.