The Germany international, who has already missed ten Bundesliga games this season due to an ankle injury, underwent tests on Wednesday morning to provide an exact diagnosis.
took Reus' place in Dresden, with initial reports from Dortmund's medical team suggesting the 25-year-old fan favourite had merely sustained a dead leg. That was confirmed on Wednesday with no damage other than bruising discovered in a scan.
Reus was ruled out of the 2014 World Cup after picking up an ankle injury less than 24 hours before he was due to fly out to Brazil with the squad. His misfortune continued after the tournament when he aggravated his ankle, missing five Bundesliga matches, before a further ankle injury picked up on 22 November ruled the former Borussia Mönchengladbach star out until the winter break.
Reus has been in scintillating form since penning a new contract in February, however, scoring five goals in as many games before the Dresden victory. His inclusion in Saturday's Bundesliga clash at Hamburger SV will be determined nearer the time.