The Black Cats boss suggests that the 28-year old centre-back has had a medical with the Canaries with a fee between the two clubs soon to be agreed.
"Negotiations are taking place at this minute with Norwich," said O'Neill.
"He's been given permission, Michael, to go down and speak to them and so we're just waiting to find out what will happen.
"Norwich have been very keen and a fee has been agreed. But we're just waiting to hear from Norwich and from Michael."