Diego has admitted he is resigned to returning to Wolfsburg when his loan spell at Atletico Madrid expires at the end of June.
The 27-year-old playmaker enjoyed a very successful campaign at the Vicente Calderon and helped the club win the Europa League.
Los Rojiblancos triumphed comfortably over Primera Liga rivals Athletic Bilbao in Bucharest, and Diego scored in the 3-0 victory.
"I think I'll be in Wolfsburg for the new season, because I still have two years left on my contract," he told German daily the Wolfsburger Allgemeine Zeitung.
The Brazil international joined the German club in a £13.3million deal from Juventus only a year after he left Werder Bremen for Turin.
However, the player was sent out on loan last summer following a public falling-out with head coach Felix Magath, although the manager has stated he was looking forward to seeing Diego return to the Bundesliga.
"He has an agreement with us from July 1. For now, we wait until the resumption of training," said Magath, who coached Die Wolfe to the 2009 league title.