Diego looks set to leave Wolfsburg in the summer after confirming he has received a "concrete offer" from Atletico Madrid.
The Brazilian spent the 2011-12 season on loan to los Colchoneros, scoring six times in 43 games and winning the Europa League in the process.
Speaking to journalists after die Wolfe's 2-2 draw with Eintracht Frankfurt on Saturday, Diego suggested that an exit from the Bundesliga is a very realistic prospect during the upcoming transfer window.
"Atletico wants me and I have been given a concrete offer," the 28-year-old midfielder was quoted by Wolfsburger Allgemeine.
"We must now speak with Wolfsburg about what is best for me and the club.
"I have always been satisfied in Wolfsburg and respect that I still have a year left on my contract.
"But that is precisely the situation that we need to talk about."
However, VFL boss Dieter Hecking is far from convinced that an offer will come in that will tempt the club to sell the former Juventus man, who scored his side's second in their final game of the season at Frankfurt.
"If his desire to go is really so great, then we need to talk with Diego," the 48-year-old German stressed.
"We have to find arguments to persuade him to stay. However, I cannot imagine that there is a club that will pay enough money for him.
"If you saw him play against Frankfurt, it is clear that clubs come and make offers. We will listen to everything and talk to him but I do not think we will do business unless an offer comes in that is so good that we cannot refuse it."