The Brazilian's representative has indicated that an agreement between the two clubs is the only thing standing in the way of a transfer to the Spanish capital side
Ribas spent several hours in discussions with Atletico sporting director Jose Caminero in a bid to reach an agreement regarding the player's potential contract at the Spanish club.
After leaving the meeting, which took place at the Vicente Calderon, Ribas revealed that personal terms have been agreed and called on the two clubs to come to an understanding.
"The situation is like this: there is an agreement with the player, the only thing left is an agreement between Atletico and Wolfsburg," the player's father said.
Reports in Spain suggest Atletico will have to spend a fee of €10 million for Diego, who joined Wolfsburg from Juventus only last summer.
The Brazil international has been deemed surplus to requirements at the Volkswagen Arena after falling out with coach Felix Magath despite having cost €15.5m, a club record transfer fee.