Teresa Varley of the Steelers' official website confirmed Green's release, adding it came "with the designation failed physical."
The 26-year-old Green only played in six games for the Steelers last season. He started 2016 on the physically unable to perform list after having offseason ankle surgery and battling headaches stemming from two concussions in a span of two weeks during the 2015 season with the San Diego Chargers.
Green missed Pittsburgh's final five games of last season, including three playoff games, due to a concussion.
In five NFL seasons with the Chargers and Steelers, Green has 95 receptions for 1,391 yards and eight touchdowns.