Ferdinand is expected to be out of action until September after suffering a setback in his battle to recover from a knee injury.
Ferdinand suffered the injury at England’s Rustenburg training camp ahead of the World Cup.
United manager Sir Alex Ferguson said: “Rio should be six weeks, maybe. It was a knee ligament injury and you’ve got to be careful with those.
“I would think he’ll be back playing in six weeks, but Gary Neville is training now after his calf injury and he started football training on Friday.
“Michael Owen is behind in that although he’s doing terrific work. I’m not sure Michael will make the start of the season but he won’t be far away. Gary will make the start.
“With the defensive injury problems we had last season, it was important to stock up at the back and we have done that by signing Chris Smalling and resolving Nemanja Vidic’s future.”