The England skipper used his own Twitter page to reject the notion that he has suffered from a recurrence of his long-standing back problems, with Ferguson claiming it was a decision purely to rest the 31-year-old, made easier by the form of Chris Smalling, who has taken no time to settle into Old Trafford life.
"Rio has come on very well in the last few weeks but the form of Chris Smalling makes it very easy for me in that respect," said Ferguson.
"Some players come to Old Trafford and take time but fortunately for the lad he has taken to it very quickly.
"He has adapted. He is receptive to training. He is intelligent. He has the physical part, is tall and quick and a good passer of the ball.
"The stage we are at with him is to give him as much experience as we can."