The Falcons have already confirmed the news.
Bethel visited with the Falcons on Monday.
Bethel, 27, is a former sixth-round pick of the Cardinals back in 2012. He played out his rookie contract before signing a four-year, $15.66 million contract that included $9 million guaranteed with Arizona back in 2015.
Bethel was set to make base salaries of $4.5 million and $5 million over the final two years of the agreement when he agreed to a restructured contract that allowed him to become an unrestricted free agent this offseason.
In 2017, Bethel appeared in all 16 games for the Cardinals and recorded 41 tackles, one interception returned for a touchdown and four pass defenses.