The move is expected to save the Texans $7.64 million under the salary cap.
During the season, Cushing served a 10-game suspension this season for violating the NFL performance-enhancing drug policy.
Cushing was selected 15th overall by the Texans in the 2009 NFL Draft.
He won the AP Defensive Rookie of the Year award and led the Texans in tackles in 2009, 2011 and 2015. In nine seasons with the Texans, he has 674 tackles, 13.5 sacks, 8 interceptions and 9 forced fumbles in 104 games.
VIDEO: Learn more about linebacker Brian Cushing
Brian Cushing facts