Keyes, 24, signed on with the Buccaneers as an undrafted free agent out of Boston College back in 2015. He had a brief stint with the Chiefs before he was eventually cut loose in October of last year.
The Falcons later added him to their practice squad and he finished out the year in Atlanta. Unfortunately, the Falcons waived him from injured reserve with a settlement a week into the 2017 regular season.
The Chargers signed him to a contract last month before waiving him on Tuesday.
In 2016, Keyes appeared in five games and recorded three tackles.