Crocker, 32, ranked seventh in tackles for the Bengals last season and didn't intercept a pass. The Bengals told him that durability was the biggest reason for the move, according to Crocker.
A defensive captain for Cincinnati, Crocker has had health issues since injuring his medial collateral ligament in 2010, which forced him to miss the last half of that season.
But he started every game last season when he played in all but 47 of the team's 1,066 defensive snaps, according to the Cincinnati Enquirer.
"I know as a player I feel a certain way but not everybody in the building felt the same way," Crocker told the Enquirer. "This was one of the best stops of my career. I got to go to the playoffs two of my three full seasons here."
Crocker's last game for the Bengals was possibly his worst. In a playoff loss at Houston, he dropped a sure interception that could have been returned for a touchdown and missed a tackle on Arian Foster that resulted in the game-clinching score in the fourth quarter.
"It's sad that I don't have a chance to redeem myself," he said.
The Bengals, who rank among the teams with the most salary-cap room, could have kept Crocker if they wanted to do so. His cap number was $2.45 million.