Borussia Dortmund will be without injured Julian Ryerson and Youssoufa Moukoko for the rest of the year and have called 17-year-old Paris Brunner into the squad for the first time for Saturday's league game against RB Leipzig, the club said on Friday.
Brunner, a forward, was voted player of the Under-17 World Cup earlier this month as Germany lifted the trophy.
"Defender Julian Ryerson suffered a ligament injury in the away game at Stuttgart (for the German Cup) on Wednesday and will not be available for the coming weeks," the club said in a statement.
"Forward Youssoufa Moukoko will miss the remaining matches of the year due to a muscle injury."
Borussia Dortmund are in fifth place in the Bundesliga, 10 points off leaders Bayer Leverkusen with three matchdays remaining before the league breaks for the winter on Dec 20. It resumes on Jan 12.
The Ruhr valley club has already qualified for the Champions League knockout stage and faces Paris St Germain in their last group match next week.