Chris Carson plans to retire after five NFL seasons because of a neck injury, a source has confirmed.

The Seattle Seahawks have released Carson with a failed physical designation.

"Ever since the first time I saw Chris on film, I loved his style, and I was thrilled when we were able to get him when we did," Pete Carroll said. "To see him grow and become such an impacting part of our program with such a great style and all of that, it was a thrill to watch. We'll miss him and everything he brought to our program."

The Seahawks have been preparing to proceed without Carson, re-signing Rashaad Penny in March before drafting Kenneth Walker III in the second round.