"I'm really appreciative for the opportunity to join this great organization and look forward to contributing everything I can to help us win games,'' Anderson told ESPN.com.
The team had an open roster spot when running back Antone Smith was placed on injured reserve with a broken leg. Anderson last was with the Tennessee Titans and also played with the New England Patriots this season.
The 31-year-old Anderson, who played college ball at Virginia Tech, enjoyed his best days as an inside linebacker with the Carolina Panthers. He was a regular starter for them from 2006-12. He led the Panthers in tackles for two seasons (145 and 130 tackles) and once had 20 tackles in a game. Anderson was a third-round draft pick of the Panthers in 2006.
He also started 16 games with the Chicago Bears last season and led the team with 102 tackles.
It will be interesting to see how the Falcons utilize Anderson, if he is a quick study. He is expected to contribute at inside linebacker, where the Falcons have Paul Worrilow, Joplo Bartu as the starters and Prince Shembo as a backup.
His immediate contribution is likely to be on special teams. He played special teams in seven games with the Titans this season.
The signing of Anderson doesn't prevent the Falcons from making another roster move before Sunday's game against Cleveland. They could easily activate Drew Davis from the physically unable to perform list by releasing another player at the bottom of the roster.