Best hasn't played since October 2011, and his return was looking increasingly unlikely. Best agreed to a five-year deal with the Lions after they drafted him in 2010, but he's played only 22 games.
"Jahvid is as fine a person and professional as I have ever worked with," Lions general manager Martin Mayhew said. "He was the consummate teammate and always did everything asked of him. We wish Jahvid the very best in all his future endeavors and have no doubt that he will be successful in whatever path he chooses."
Best accounted for 1,000-plus yards and six touchdowns as a rookie, but was limited to six games during the 2011 season after what he said was the third concussion of his football career. He hasn't played since a loss to San Francisco in 2011.
Best also missed time during the preseason that year because of a concussion, and when he was a college player at California, he missed a few games after a fall knocked him out and sent him to the hospital with a concussion and sore back.
"I want to thank the Detroit Lions organization for drafting me and giving me an opportunity to fulfill my dream and play in the National Football League," Best said in a statement provided by the team. "My time as a member of the Lions was a very special time in my life. My teammates, the members of the organization, the Lions fans and the people of Detroit will hold a special place in my heart. I'll always be a Lion."
Detroit signed Reggie Bush in the offseason to help boost its inconsistent running game.
Best began last season on the physically unable to perform list, and after six weeks, Mayhew said Best hadn't been permitted to return after a consultation with medical experts.