The 6-foot-3, 234-pound Tripp entered the NFL as a fifth-round draft pick of the Miami Dolphins in 2014 out of Montana. He spent last season with Green Bay and recently was released during the Packers' final roster cuts.
The Falcons became thin at linebacker after reserve LaRoy Reynolds was placed on injured reserve Monday. Although Reynolds could possibly return midseason, the Falcons needed to find another body to back up starting middle linebacker Deion Jones and to fill a void on special teams.
Tripp was Green Bay's special-teams captain during the preseason and made an impact on special teams for the Packers last postseason, leading the team with four combined special-teams tackles in two playoff games.
Tripp played 13 games during his rookie season with the Dolphins. He then went to Jacksonville in 2015 and played 12 games with the Jaguars, with one start.
Last season, Tripp was with the Seattle Seahawks' practice squad to start the season and was then elevated to the active roster due to injuries at his position. Tripp played in seven games with one start for the Seahawks before sustaining a quadriceps bruise and knee injury that led to him being waived/injured. He finished the season with the Packers, appearing in two regular-season games and two playoff contests.
Tripp is familiar playing both the middle and weakside linebacker positions in Falcons coach Dan Quinn's schemes based on his time in Seattle. Quinn was the Seahawks' defensive coordinator before coming to Atlanta, and Seattle still runs the same system.
At the 2014 NFL combine, Tripp tied former Falcon A.J. Hawk's 20-yard shuttle record for linebackers at 3.96 seconds.
As for Douglas, the 2015 fourth-round draft pick by the Dolphins was last on the New England Patriots' practice squad in October 2016.