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 reached its next milestone on Tuesday, with the winger posting a video on Instagram, since deleted, of himself on a stationary exercise bike at the club's training complex.
The Germany international's progress was confirmed on Wednesday when he was pictured walking with a supporting brace around his right knee at Dortmund's annual pre-season Media Day, alongside fellow midfielder Julian Weigl, who is likewise working towards a comeback after breaking his ankle.
Although Dortmund have plenty of cover in attacking midfield, with the likes of Christian Pulisic, Mario Götze, Andre Schürrle and Ousmane Dembele, 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