Ferguson is concerned Ferdinand's fitness regime will be disrupted by his return to the international fold.
Hodgson said: "I have spoken to Sir Alex about Rio but I'm not going to go into detail about conversations I've had with other managers.
"Sir Alex is an important person for me to keep in touch with but I'm not prepared ever to discuss the content of our conversation.
"That will remain private between us.
"Whenever players come to join us, we always research what their routines are with their club sides, what they are used to doing two days after a match for example or the day before a game.
"To such extent, we take that into account with our programme and our medical people are in constant contact with the medical people and sports science people at all the clubs.
"It gives us a pretty good idea of what needs to be done. I think it is very important. I regard myself as a custodian of these players."