Atlanta announced its acquisition of Richards in a trade with the New England Patriots on Friday.
Per NFL Network's Ian Rapoport, the Patriots will receive a conditional 2020 seventh-round draft pick in the deal.
The move comes as teams are deciding who to keep leading up to Saturday's 4 p.m. ET deadline to get their rosters down to 53 players.
Richards struggled to find a consistent role with the Patriots. He was a second-round pick in the 2015 NFL draft and appeared in 41 games over the past three seasons. The former Stanford standout started a career-high five games in 2017 but was primarily playing behind Patrick Chung and Duron Harmon.
The Falcons will give Richards an opportunity to compete for playing time. Keanu Neal and Ricardo Allen are their starting safeties, with Ron Parker and Damontae Kazee in backup roles.
Richards recorded a career-high 26 combined tackles in 16 games for the Patriots last season.