Stephen Pears is expected to be named new goalkeeper coach at Middlesbrough.
"Paul is still with us at present but he has been in talks with Newcastle and we are expecting that will happen and he will move on," said Southgate. "There was a long-standing agreement that he would go with Australia to London this week.
"Obviously it meant he can work with Mark Schwarzer, which benefits us. Everything is still to be finalised and there is no replacement lined up at the moment. But obviously Stephen Pears is with us and I'm keen for him to have an opportunity and see how it goes."
Pears will be a popular appointment with Boro fans - he was a terrace favourite during his time with the club before leaving for Liverpool in 1995.