Kagawa helped Dortmund win the Bundesliga in 2011 and 2012 in his two seasons at the club after moving from Japanese side Cerezo Osaka for a reported fee of 350,000 euros ($460,000).
He scored 21 goals and set up 12 more in 49 Bundesliga games for Dortmund, despite missing six months with a broken foot. He also scored with former Manchester United coach Alex Ferguson watching in the stands as Dortmund beat Bayern Munich 5-2 in the 2012 German Cup final.
However, after moving to Manchester for a reported fee of around 16 million euros ($21 million), Kagawa struggled to impress in the Premier League. He played in only 38 league games from a possible 78, seven as a substitute, while he was taken off in 21.