The 28-year-old sustained ligament damage in Dortmund's DFB Cup final triumph over Eintracht Frankfurt in May and underwent successful surgery in early June, ruling him out of action until 2018.
His long road back to full fitness began soon after and he was shown beginning exercises in August and now having returned to running on a treadmill for the first time this year has taken the next step and has his feet back on the training pitch.
The winger - who recently said "I would give away all my money to be healthy again" - could be seen letting his legs do the talking at Dortmund's training ground in Brackel on Monday morning.
The German international is expexted to return at the start of 2018, but said in an interview with GQ magazine last month that he won't set a date on his return, and will allow his body to tell him when it's ready.
Although Dortmund have plenty of cover in attacking midfield, with the likes of Christian Pulisic, Maximilian Philipp, Mario Götze, Andrey YarmolenkoAndre Schürrle and among others, shouldering responsibility in his absence, Reus is a guaranteed starter when fit.
He missed 16 games due to injury in 2016/17, but scored seven goals in 17 Bundesliga outings, adding a further four in as many UEFA Champions League appearances.
Watch: Reus' top 5 Bundesliga goals in 2016/17