The 27-year-old represented Germany as a youth player, but having been born in the Russian town of Kozhevnikovo and not played competitive senior international football for any other nation fulfils FIFA's eligibility requirements.
"I'd like to be involved [for Russia], but I haven't heard anything yet" Rausch was reported as saying earlier this summer. "You should never give up hope, hopefully someone in charge will notice me."
Russia head coach Stanislav Cherchesov has clearly been impressed by the performances of the Bundesliga stalwart who, with 234 German top-flight appearances under his belt, will link up with the 2018 World Cup hosts during the August-September international break.
Rausch would not be the first Germany player to switch his allegiance to Russia. Ukraine-born former Borussia Mönchengladbach and Schalke midfielder Roman Neustädter was granted a Russian passport in time to appear at UEFA EURO 2016, having been capped twice at senior level by Die Nationalmannschaft