Sunderland have struck terms with Panathinaikos for Charas Mavrias.
Sunderland will pay £2.5 million for the Greece international.
The Black Cats are closing in on a deal for the Greek teenager, holding talks with Panathinaikos director - and former Newcastle United defender - Nikos Dabizas.
And reports in Greece suggest that an agreement for the 19-year-old could be pushed through over the next 24 hours.