Schlotterbeck was forced to leave Germany's final training session on Wednesday after going down in pain while Jürgen Klopp watched on. He subsequently underwent further examination on his right ankle.
The German Football Association confirmed that the 26-year-old has suffered an ankle ligament injury and will miss Germany's next two Nations League matches against Serbia and Greece. No replacement will be called up to the squad.
The setback comes just weeks after Schlotterbeck returned from a serious left ankle injury sustained during Germany's 2026 FIFA World Cup campaign. That injury ruled him out for several months.
Schlotterbeck had played the full 90 minutes in Klopp's first match as Germany coach, a 1–1 draw away to the Netherlands. He was then left out of the squad for Germany's subsequent 1–0 defeat by Greece.
His latest absence leaves Klopp with another selection issue ahead of the meeting with Serbia. Young defender Finn Jeltsch is among the players who could step into the defence, having been included in what Flashscore described as Klopp's second squad for the international window.
Klopp is still searching for his first victory as Germany coach after a draw against the Netherlands and defeat to Greece. Germany currently have one point from their opening two Nations League matches, while Serbia have also lost both of their games.
The Germany-Serbia match is scheduled for Thursday in Munich.