Dortmund - Borussia Dortmund lured Germany forward Mario Gotze back to the Westfalenstadion from Bayern Munich on a four-year contract.
Gotze left Dortmund for Bayern in 2013 but never settled down and was mostly a bench player under previous coach Pep Guardiola.
New Bayern coach Carlo Ancelotti had a talk with Goetze before assuming the post and reportedly did not try to keep the forward, who scored the winning extra-time goal for Germany in the 2014 World Cup held Brazil.
At the European Championship in France that ended earlier this month, Gotze did not play a major role.
"When I switched from BVB to Bayern in 2013 that was a conscious decision behind [which] I will not hide myself today," said Gotze as quoted by Sky Sports.
"Three years later, and with 24 years of age, I look with different eyes at my former decision. I can well understand that many fans could not understand my decision. I would not even take it so today.
"When I return to my home, I want to try to convince all people by my performances - especially those who do not receive me with open arms - that my aim is to play my best football again. For all of us, the club and the BVB fans."