The Argentinian defender joined City at the start of September from Atletico Madrid but damaged knee ligaments in his first week of training.
Demichelis played 45 minutes in the elite development squad's 2-2 draw with Rochdale on Wednesday night.
Martin Demichelis: "It was important to play and get the confidence back. My knee responded very well and I'm very happy after working very hard to get here.
"It was difficult at the beginning with the injury but that allowed me to meet everybody at the club and feel confident and comfortable with everybody so it's fantastic now and I'm looking forward to my debut."