It had been four months since the former Birmingham City boss had been managing in person for the club, after contracting COVID-19 and spending two spells in hospital - including a short stay in intensive care.
Town went a full 24 matches without their boss in the dugout.
The club confirmed that the 56-year-old would be in attendance for the fixture with Oxford earlier this week, and was pictured ahead of the game speaking with Oxford United boss Karl Robinson, alongside Dave Edwards.
Aaron Wilbraham and David Longwell have been standing in for the Town boss during his time away from match action, with Cotterill maintaining contact through games and holding team talks with players remotely.
Take a look at our gallery here as Cotterill made his return pitchside.