The seven-time Pro Bowler and three-time first-team All-Pro was a solid rotational pass rusher for Atlanta a year ago, tallying three sacks in 15 games.
The talented defensive player had been on three different teams over the last four years after spending his first 11 seasons in the National Football League starring with the Indianapolis Colts.
Freeney started two of Atlanta's three postseason games, registering a sack, a tackle for loss and three quarterback hits. His 122.5 career sacks rank 18 all-time and second among active players behind Julius Peppers.
Freeney's deal is for one year, a source told ESPN's Adam Schefter.
Avril, 31, has been reported as wanting to continue to play but the team is waiting to see if doctors will give clearance for him to take the field again. But the bigger concern is in the depth behind Clark and Michael Bennett, who is also dealing with a plantar fascia injury. Avril was later placed on injured reserve. The Seahawks also have Quinton Jefferson and Branden Jefferson as ends. He didn't play tons of snaps in Atlanta, averaging 28 per game.
Freeney played his first 11 seasons with the Colts, winning a Super Bowl ring with Indianapolis following the 2006 season. He had 8.0 sacks in just 11 games the previous year with the Arizona Cardinals.