Neither club revealed the financial details of the deal but reports in the German media said Dortmund had paid around 20 million euros ($24 million) for the 26-year-old.
Delaney played 32 league games for Bremen last season, scoring three goals and providing five assists. He is Dortmund’s third acquisition in the close season after they signed goalkeeper Marwin Hitz from Augsburg and midfielder Marius Wolf from Eintracht Frankfurt.
