The 21 year-old was released by Blackburn and returns to Don Valley after his loan stint at the back end of last season.
"Marcus is still very young and has the potential to go far but the step up is huge to Premier League Football. We're looking forward to working with him," said Chief Operating Officer Paul Douglas to the clubs official website.
MillersMAD wish him every success, with more signings expected to be made by the weekend, one of which is Bury defender Ryan Cresswell.