Onuoha played the full 90 minutes for City against the United Arab Emirates in Abu Dhabi on Thursday and may make Saturday's squad.
"It's good to be back," said Onuoha. "It's been frustrating for me for the past few weeks, having to watch things from the sidelines.
"When you can see the team has so much potential to do well, you need to be 100 per cent just to get a place in the squad. Hopefully I've taken the right steps towards playing again."