Former Germany forward Mike Hanke has retired at the age of 31, saying he has lost his appetite for the game.
Wolfsburg reduced Bayern Munich's deficit at the top of the Bundesliga to 11 points after a 2-1 win over Cologne.
Borussia Dortmund remain in the Bundesliga relegation play-off spot after a 2-2 draw with second-placed Wolfsburg.
Borussia Dortmund threw away their lead twice to pick up only a point as they drew 2-2 at home to Wolfsburg.
China star Zhang Xizhe's first press conference for Wolfsburg was set to attract a TV audience of 50 million in his home country.
Wolfsburg were frustrated by a plucky Paderborn side as they drew 1-1 on Sunday afternoon.
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