The centre-back has admitted that the 1996 European champions were not good enough this summer, and will have to be better in Brazil in two years' time
The much-fancied Mannschaft were beaten by Italy in the semi-finals of Euro 2012, and the Borussia Dortmund defender is adamant that they have to make significant steps forward ahead of the tournament in Brazil.
"With the performances we gave at the Euros, I don't think we have a realistic chance of beating the top nations in the decisive games and becoming world champions," he told Kicker.
"We have got to get a lot better. Apart from the Greece game, we were always taking the tempo out of matches."
Hummels then looked back at Germany's loss at the hands of the Azzurri, and stressed that their cautious approach cost them the game, and not just his first-half error that allowed Mario Balotelli to open the scoring.
"The big difference was that Italy took far more risks while we placed huge emphasis on being cautious. You have got to recognise that we were the worst team in that game and we would have lost even without my mistake."