Ferdinand's injury problems mean he has played a limited part in the champions' season so far, and his contract is due to expire this summer, but Redknapp has played down suggestions he will bid for either of the duo when the transfer window opens.
"I haven't even thought about Rio to be honest," Redknapp said.
"I signed him as a kid. I love Rio as a boy and a player, but it's not something we have ever enquired about.
"It's going to be difficult for him to leave Man United isn't it?"