The 32-year-old has been with the club for five years and was a regular player up to this season, when he has struggled to get game time at left-back ahead of Norman Theuerkauf and new signing Jonas Föhrenbach.
His contract will though be temporarily be extended if Heidenheim reach the play-off for a place in the Bundesliga, with his side currently in pole position after their win against Hamburg.
Holger Sanwald, the club’s CEO, said that Feick “has been a top performer over the years and has always proven himself to be a team player,” and thanked him for his “passionate commitment and achievements” over the past few years.
He also confirmed that a role would be made available for Feick once he ends his playing career.
He is the second long-serving player to have his departure confirmed, although the retiring Robert Strauß will become an assistant to the board at the end of the campaign.
Timo Beermann, Sebastian Griesbeck and Maurice Multhaup remain without a contract for next season.