The Brazilian forward - who has just returned to Wolfsburg after a year's loan deal when he helped Atletico win the Europa League last season - has had spells with Juventus, Werder Bremen and Wolfsburg, where he has returned following a falling out with the club's coach Felix Magath last year.
"All three of them are absolutely top leagues," said Diego. "I would say that, after the Premier League, the Bundesliga is the second strongest and most attractive league in the world. The new stadiums, the incredible popularity amongst the fans and the superbly run clubs: the Bundesliga has evolved tremendously over the past few years and has already overtaken Spain and Italy in that respect."
Diego is hoping to add to his 33 caps by impressing with Magath's side ahead of the 2014 World Cup in his homeland.
"That's a big goal of mine," said Diego. "I'm still hoping to receive a call-up and I'm ready if that's the case. To be able to take to pitch during a World Cup in your own country is the greatest possible experience for any footballer.