"We're delighted that Sokratis has decided to join Dortmund," said BVB sporting director Michael Zorc. "He can play in several positions across the back and we see a lot of potential in him."
"The next step"
Sokratis joined Bremen in 2011 from Italian outfit Genoa CFC, making 59 appearances and scoring two goals for the club in the Bundesliga and DFB Cup. "I've had two years in Bremen from which I've profited greatly," said the defender. "Now it's time for me to make the next step."
Both clubs have agreed to keep the financial details of the transfer confidential.