The 35-year-old has been limited to just 12 appearances this season and has not featured since the Champions League defeat of Shakhtar Donetsk on December 10.
That has led to claims Ferdinand will end what is to become a 14-year association with the Old Trafford outfit when his present contract comes to an end in the summer.
However, Moyes has not necessarily reached that conclusion and, ahead of the New Years' Day encounter with Tottenham, feels Ferdinand can make a continued contribution.
"Rio has had a few injuries and little niggles in his calf," said Moyes.
"But, overall, he is very much part of it.
"Rio and Vida [Nemanja Vidic] have been two of the best centre-backs in this Premier League generation. For the past 10 years, they've been terrific.
"I will continue using them but there are always going to be other people to come in. This club has to have a line of players ready to take their places and push them.
"The challenge is for the young players to take over. It's part of the job if you play for this club."
It is widely acknowledged he requires midfield reinforcements though, with Moyes claiming even Sir Alex Ferguson felt his squad needed fresh blood when he stood down last May.
"I think, if he had been here, Sir Alex would have said that there needed to be a rebuilding job as there is a continual building job going on all the time," said Moyes.
"First and foremost, we always look to the academy to see if we can bring players through. Who are the next ones possibly coming up to the first team?
"After that, if we've not got a position covered, we will go out and try to find something better than what we've got."
The obvious problem Moyes is facing is that the January transfer window is not the greatest time to get the right men.
Asked if he would be relaxed if he has not added to the squad when this month's transfer window closes, Moyes replied: "I don't know if I'd use that word. I would say I'd liked to do something and tried to do something. We'll try to get close to doing something if possible."
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- Shakhtar Donetsk
- Nemanja Vidic