The attacker was forced to miss his nation's victorious World Cup campaign in Brazil when he tore ligaments in his left ankle in the build-up to the finals.
Reus has since made his return to action and has been in fine goalscoring form for Borussia Dortmund, netting five goals in 10 appearances in all competitions.
He was dealt a blow on Monday, however, with the news that he would miss Germany's Euro 2016 qualifier against Gibraltar on Friday, as well as the friendly clash with Spain four days later.
"Marco Reus will have to sit out the final two internationals of the year," read a statement on the German Football Association's official website, with no replacement named.
"The Germany international and Borussia Dortmund star is suffering from a torn ligament and tendon as well as a swollen ankle.
"The 25-year-old picked up the injury in Dortmund's 1-0 victory over former club Borussia Monchengladbach on Sunday.
"It is hoped that the attacker will be available for their next Bundesliga game, which is against SC Paderborn (22nd November). The injury was discovered on Monday morning."
