However, following almost a year on the sidelines, Hargreaves believes he is nearing a return to playing first team football.
"I have thought about playing again a lot. It is human nature to have doubts obviously," he has told the Manchester Evening News.
"I had little moments but I never had one moment of major doubt that I'd be back.
"It is difficult to say an exact date but I do feel I can see light at the end of the tunnel now.
"Coming back to Manchester was a big step. Having people from United around me also makes me realise I am getting closer.
"I am coming back to have a massive effect and to play well and for us to win titles.
"It is not about getting back for one game or for one day, I want to come back and be back for another six or eight years."