The 34-year-old Friedrich, who represented Germany 82 times, had been combatting injuries that prevented him from playing at all this season. He appeared in 23 MLS games for the Fire in his first season in the league in 2012 and was named the club's Defender of the Year after joining from VfL Wolfsburg. He had been signed to a new deal for the 2013 season in November.
Friedrich had resumed training with the Fire at the end of March only to return to his native Germany at the end of May to seek treatment on his hip. He also cited two herniated discs in his back on the announcement on his website.
With Friedrich unable to perform, the Fire traded for Philadelphia center back Bakary Soumare to help augment its back line, a sign that Friedrich's recovery was not accelerating as hoped. The club is 3-0-2 in league play since the transaction and has also advanced to the quarterfinals of the U.S. Open Cup.