"You can't get better back-to-back matches than United followed by England," he told Manchester Online.
"I'm hoping to start training fully with the City squad next week but until I am 100%, I won't be risking anything.
"You have to take things one day at a time with this kind of injury. You cannot force the issue and end up injuring yourself again and being out for the season.
"I'm doing all the right things, doing strength work. In the Premiership, which is such a tough league, you have just got to be spot on fitness-wise.
"It would be brilliant to get back in time for those two games next month. It is tricky pitching things right and knowing when to step up the training, but there are plenty of people around to advise me about that."