Shelby, 28, originally signed now with the Dolphins as an undrafted free agent out of back in 2012. He played out his rookie contract with Miami before joining the Falcons for the 2016 season.
Shelby was entering the third year of his four-year, $18 million contract that included $7.5 million guaranteed and set to make base salaries of $4.5 million over the final two years of the agreement.
According to OverTheCap.com, releasing Shelby will free up $3.25 million of available cap space while creating $2.5 million in dead money.
In 2017, Shelby appeared in all 16 games for the Falcons and recorded 30 tackles and a sack.