Hargreaves told MUTV:
"It's been very stop and start.
"You just want to get involved, it's great to get back in the team and have a game, especially when the game is won.
"I've been out for quite some time, so I'm a bit sore, a bit stiff, but those things are part and parcel when you've been out. We've got a few days before the Arsenal game, so we'll try and do things right so that I'm fit."
"It's been frustrating because I've really had it since the end of last season.
"I've spoken to a lot of doctors and specialists, and they've explained to me that it's not really a problem with the knee, it's a structural problem with the biomechanics.
"For some reason my body's not happy with the way it is, so you need insoles and things to correct that. I've been trying to get round it and find the answer because I don't want to miss any games, I want to be fit for the rest of the season."
Ferguson:
"Owen is a different player to anyone else we have got. He has fantastic speed and sees danger very well. He is a fantastic addition to our squad.
"Of course he has been frustrated. He came for a big fee and has only played three games, which is not what he is here for. But he is back now, and if he stays back, that is terrific news for us and only gives us a better chance of doing well."