Moyes could turn to the former England international for Sunday's home game against Fulham.
"Rio is back training. He's back and we will continue to use Rio at the right times and the right moments," said Moyes.
"Rio has made a great contribution, especially in the first half of the season. I played him in nearly all the opening eight to 10 games. He was a big part in helping me to settle.
"He has competition at centre-half but he is very much valued and looked at as one of the senior players."
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