The Falcons waived Collins last month after he completed a 10-game suspension for a second violation of the NFL policy on performance-enhancing substances.
Collins, 24, has not signed with any team since going unclaimed on waivers last month.
The reason for Collins' suspension is unclear, but it's unlikely he violated the PED policy for a third time. According to the league's policy, a third violation would trigger a suspension of at least two years.
Collins, a 2015 second-round draft pick from LSU, was suspended for the first four games of the 2016 season for his initial violation of the PED policy.
Collins has two interceptions, 10 passes defensed and 42 tackles in 24 career games (eight starts).
ESPN's Vaughn McClure contributed to this report.