The move came only two days after the team released running back Warrick Dunn. Four-time Pro Bowl tight end Alge Crumpler, offensive tackle Wayne Gandy and quarterback Byron Leftwich were released last month.
The release of Harrington, who started 10 games last season, may increase the odds Atlanta will select a quarterback with the No. 3 overall pick in next month's NFL draft.
Harrington had 2,215 yards passing with seven touchdown passes and eight interceptions last season.
The Falcons re-signed Chris Redman to a two-year deal. Excluding Michael Vick, who was sentenced in December to 23 months in federal prison, the only other quarterback on the roster is D.J. Shockley, who missed last season with a knee injury.
Copyright 2008 by The Associated Press