Santiago Vergini has left the black cats to join Club Atletico Boca Juniors for an undisclosed fee.
Vergini, who was first loaned to us from Estudiantes, made 51 appearances for us since joining in 2014. The centre back was then loaned out to Getafe last season where he made 25 appearances.
He has now returned to his home country of Argentina to play for Club Atletico Boca Juniors despite failing his medical with them earlier this week, for a rumoured fee of around £1.5 million, though no fee has officially been announced.
We wish him all the best in the future with his new club.