Long, 29, had two years remaining on his four-year, $34 million contract that included $16 million guaranteed.
According to OverTheCap.com, releasing Long will free up $8 million in available cap space while creating $2.5 million in dead money.
In 2014, Long was limited to appearing in seven games and playing a total of 449 snaps, according to Pro Football Focus. Long ultimately graded out as the No. 36 offensive tackle out of 84 qualifying players in 2014.