Germany coach Joachim Low believes Michael Ballack can still have an impact at Chelsea.
The 30-year-old midfielder has been linked with a move to Real Madrid after failing to find his best form during his first year in London.
But when asked whether Ballack is suited to the English game, Low defended his national-team captain.
'Without a doubt Michael Ballack is a world-class player,' he told German newspaper Die Welt.
'I don't see things so negatively. He played in a lot of matches and, on the national team, one could see that he has improved, especially physically. He will succeed.'