Heiko Westermann and Hamburg have come to a mutual agreement not to renew his contract.
The centre-back joined Hamburg in 2010 and has made 173 competitive appearances for the Bundesliga club.
But, after Hamburg survived relegation in a play-off for the second straight year, Westermann - who boasts 27 caps for Germany - has agreed to end his spell at the Imtech Arena.
Westermann's contract with Hamburg expires next Tuesday.
"Heiko has given his all for Hamburg for five years," chairman Dietmar Beiersdorfer told the club's official website.
"We have the highest respect for his highly professional attitude and wish Heiko all the best for the future."
Westermann added: "I hope that the proposed, new route will be exactly right for Hamburg and that they can stablise the entire club.
"For me now it's a few days on holiday. I do not know where I will go after that, but I will take my time and decide in peace.
"I want to say thank you to people who have always supported me, even in difficult times. And the fans, who believed in the team and pushed them especially in the crucial stages."
