Reus fired Germany into a 44th-minute lead on Tuesday but was injured in the process.
"Reus suffered only a bruise in his foot. That is the result of a medical check today," Dortmund said.
"His participation in the league game against Bayer Leverkusen on Saturday is not in danger."
The German footballer of the year joined two-times defending Bundesliga champions Dortmund from Borussia Moenchengladbach in the close season in a deal reportedly worth 17 million euros.
Dortmund are in sixth place in the standings on four points from two games, two behind leaders Bayern Munich, with Reus having scored once.