Reid appeared to confirm the news on Twitter.
Carolina's staff, led by new head coach Matt Rhule, considered the 28-year-old a great fit for the team's culture but opted to take a different approach to the safety position in free agency, according to Darlington.
Reid signed with the Panthers in 2018 and started all 29 games in which he played, accumulating 147 tackles, five sacks, and one interception.
The veteran defender was the first player to join Colin Kaepernick in kneeling during the U.S. national anthem in 2016 to protest social injustice. He's among the league's most outspoken individuals regarding social injustice.