Hargreaves last game for United was in September 2008, then he had to go for knee surgery in America to try to cure a chronic tendinitis problem.
The 29-year-old eventually returned to United's Carrington training base 12 months later after undergoing an extensive rehabilitation programme under the guidance of world renowned knee specialist Dr Richard Steadman.
It was hoped that Hargreaves would have been back in action by November and looking at earning a place in the England squad for the World Cup.
Now here we are in February and Ferguson opted to leave the player out of his 25-man Champions League squad, which had to be submitted to UEFA by the end of last month.
Yet Ferguson insists the bad news need not necessarily prove terminal.
He said: "Owen's recovery is slow. It is a year and a half now and I can't put a time on it. But he will be back. He could come back and make an impact on the league for us. Hopefully he does."