Norwood, a third-round draft pick by the Falcons in 2006, had just 76 carries for 252 yards and no touchdowns in 2009. He had head and hip injuries and was inactive for six games.
Norwood has 1,987 rushing yards and seven touchdowns in his four-year NFL career. He ranks third in Falcons history with 2,987 yards on kickoff returns.
Koenen averaged 42.6 yards on 61 punts last season, his sixth with the team. He also was the team's kickoff specialist.
Backup tight end Jason Radar, who made one start in 2008, also announced his retirement.
Copyright 2010 by The Associated Press