USA Today's Tom Pelissero reports ex-Lions RB Jahvid Best hasn't given up on resuming his career, but is "not cleared at this point." Best was waived in July, more than 21 months after his most recent snap. Best is still only 24, but the fact is, no NFL team is going to medically clear a player with his concussion history. Best should give up the ghost at some point in the near future.