Former Germany defender Arne Friedrich says he is retiring from professional football and has asked the Chicago Fire to terminate his contract for the MLS team.
The 34-year-old Friedrich wrote on his website Sunday that he took the decision after "much consideration and consultation" with his doctors.
He said he has experienced increasing back pain in recent weeks. He added: "With two herniated disks in my lower back, I am no longer able to fulfill the demands of a professional soccer player."
Friedrich formerly played for Hertha Berlin and Wolfsburg. He made 82 appearances for Germany.