Schlotterbeck's World Cup is over after Germany's medical staff confirmed the Borussia Dortmund defender has torn the medial ligament in his left ankle — an injury that will sideline him for several months and casts serious doubt over a potential summer transfer.
The 26-year-old was hurt during Germany's 2-1 win over Ivory Coast in Toronto after a challenge with Amad Diallo in the first half. Schlotterbeck played through to half-time before being replaced by Antonio Rüdiger and then flying back to Germany's base in Winston-Salem for an MRI scan that confirmed the damage.
Germany head coach Julian Nagelsmann gave his verdict after the game.
"Schlotti will be greatly missed on the pitch as an outstanding defender, especially for his excellent build-up play. This could have been his World Cup.
"Despite his absence, we are still very well covered at centre-back with Jonathan Tah, Antonio Rüdiger, Waldemar Anton and Malick Thiaw for the World Cup."
Schlotterbeck had started both of Germany's group games, scoring against Curaçao in the opening match. Rüdiger, returning from his own injury layoff, is now expected to slot back into the starting eleven.
The timing also complicates a possible departure from Dortmund this summer. A release clause of €50 million in Schlotterbeck's recently extended contract was available to Real Madrid, Barcelona or Liverpool until mid-July. That window will likely pass before the player is in any condition to complete a transfer.
The DFB confirmed he will initially remain with the squad in the United States rather than return to Germany immediately.