The front office gave no reason for the abrupt termination.
Doucet signed with Seattle as a free agent on Aug. 2.
Doucet was Arizona’s third-round selection in the 2008 NFL Draft and played in 54 games with 14 starts in his five seasons with the Cardinals.
Last year, he played in 12 games and had 28 receptions for 207 yards. For his NFL career, Doucet has 139 receptions for 1,491 yards and seven touchdowns. Arizona released him on March 9, 2013.