Reports in Italy suggest that Santon has reached the appearance tally which triggers the move to the San Siro on a full-time basis.
After playing his 10th game in 1-1 draw with Cesena his exit at Newcastle is seemingly confirmed.
It is understood that Newcastle will now pick up £2.8m for the deal which sees Santon back at Inter on a permanent basis.
Santon left the club in January on a season-long loan with a view to a permanent move.