The Falcons will likely place him on the reserve/retired list in the coming days, which will ensure that they hold his rights if he elects to return to the NFL at some point.
Thornton, 25, is a former third-round pick of the Colts back in 2013. He played out his four-year, $2,735,380 contract with the Colts and was testing the open market as an unrestricted free agent for the first time in his career when he signed a one-year contract with the Falcons.
Thornton was set to make a base salary of $690,000 for the 2017 season.
Unfortunately, Thornton missed the entire 2016 season after he was placed on injured reserve with a foot injury coming out of the preseason.
For his career, Thornton appeared in 37 games for the Colts.