United have been linked with Rodwell for the past two seasons and press speculation has suggested that the two clubs have agreed a fee for the England Under-21 international to tread the same path as Wayne Rooney in 2004.
Moyes insisted: "We are not vulnerable. I have heard the stories about Jack and they are a load of rubbish.
"We have a great working relationship with Manchester United. The chairman (Bill Kenwright) has a great relationship with David Gill and I have with Sir Alex (Ferguson).
"To say that a deal is already done for Jack is completely untrue and I don't know where those stories have come from."