The Reds centre-back was told he would have to adjust his game as he gets older and that led to some newspaper reports that the £30million signing from Leeds will be phased out of the firing line.
Sir Alex addressed the matter on the eve of Saturday's 1-1 draw with Newcastle United, during which Ferdinand was highly unfortunate to concede a penalty. The boss told Sunday newspaper journalists:
"I think it [the talk about Rio's United days being numbered] generally came from the media after he'd not played in certain games.
"From Rio's perspective as he's been such a great player for us, I think it was important to explain his present position and there's nothing wrong with that.
"What I said was absolute fact - he's not as quick as he was five years ago. That happens, people do lose their pace as they get older.
"But Rio is adjusting his game accordingly and has had two or three good performances since then.
"I've no issues at all with Rio, he can play for another couple of years quite easily. Of course we have to look ahead, there's nothing wrong with that, but it shouldn't mean Rio looks upon it as the end of his career. He's got a part to play with his experience and he's good in the dressing room. He's a big figure and players look up to him so that will continue."
Sir Alex echoed these sentiments in his interview with the latest edition of Inside United, which is on sale from Wednesday 30 November.