Neven Subotic has ended his long-term stay with Dortmund, joining Ligue 1 side Saint-Etienne.
Subotic has played for Dortmund since joining from Mainz in 2008 and played a key role in their back-to-back Bundesliga triumph.
Injury has hampered his time over the last two seasons and he will now continue his career in France.
“I would like to thank BVB wholeheartedly for the nine years at BVB,” he said in a statement on Dortmund’s website.
“Over the years, we have experienced many things together, mourned together and celebrated together. This time I will forever carry in my heart.
“Thanks to all Borussia fans for this wonderful time, because without your support, they would not have been possible. It was an honour for me to celebrate big titles for our team and the whole city.
“These moments have connected me with BVB and especially with the people behind it. This connection will last forever.”