Hargreaves has managed just one minute of senior action in the past two years since undergoing surgery on both knees to try to cure a tendinitis problem.
Further doubts over the England midfielder's career were raised this summer when Ferguson sent him back to Dr Richard Steadman in Colorado after he experienced more discomfort during pre-season training.
Ferguson revealed earlier this month that Hargreaves would be returning to England in the near future and that encouragement was enhanced by Steadman's recent observations about how well the 29-year-old has been progressing.
Even so, no-one expected the United boss to be openly talking about Hargreaves actually playing quite so soon.
Yet, after seeing the midfielder in action on the training ground at Carrington this week, Ferguson is feeling quite bullish about a successful comeback.
"Owen has looked very good," he told MUTV.
"After being out for so long, we'll obviously have to monitor him and see how he's going to progress in the next few weeks. But it's good to see him back.
"Because he's been out for so long you have to see whether there's going to be a relapse.
"That's the first thing on our mind at the moment but having watched him in training yesterday if he continues that way he's going to give me another selection problem, no question about that."
Another England star on the way back is Michael Carrick, who had an injection in his Achilles earlier this month to try to ease some growing discomfort.
Like Hargreaves, Carrick will not come into contention for Sunday's trip to Bolton but Ferguson is delighted with the 29-year-old's progress.
"It was nothing serious, just one of those niggling little problems you can get with your Achilles, particularly at the start of the season when grounds are firm," said the United boss.
"But he is fine and has started training."
As the Red Devils are now in a run of two games a week, Ferguson needs as many options as possible.
Some games are more important than others though, which is why he bypassed the Carling Cup trip to Scunthorpe on Wednesday in preference for a scouting mission in Valencia, United's next Champions League opponents on Wednesday.
It was only the third game Ferguson has missed in his 24-year stint as manager, which emphasises the importance he is placing on the trip to Spain.
That could also play a part in his team selection at the Reebok Stadium, although at least he will have one in-form striker in Dimitar Berbatov, who took his tally for the season to seven last weekend with his brilliant hat-trick against Liverpool, in the ranks.
"Any time you have a successful season you've always got a striker who's got you 25 goals and upwards," Ferguson told Key103.
"We have had it with Cristiano Ronaldo, Wayne Rooney last season and others before that.
"You want players who could get a percentage of goals that make the difference.
"If Dimitar keeps doing that, he's going to be the one this season."
That is not to discount Rooney.
Ferguson might be concerned at the scrutiny his star striker is under just now.
However, he is convinced Rooney's current lack of goals - a single effort from the penalty spot - is a temporary aberration.
"Wayne will get his form back, there is no doubt about that," he said.
"He just needs to get a couple of goals. That is down to confidence."
With big games coming up on a regular basis, Rooney will not be getting many rests, although as midfielder Darren Fletcher can testify after missing his first game of the season in midweek, that can be a good thing.
"You want to play every game," he said.
"We all know it is a squad game and we have plenty of strength in depth.
"But once you are in the team you want to stay in it.
"You enjoy the momentum it brings.
"When you get minutes under your belt, your touch and sharpness seems to be there."