A former NFL player who suffered what the league deemed a career-ending concussion has sued insurer Lloyd’s of London for denying a $1 million insurance policy for professional athletes. The lawsuit, filed this week in North Carolina, could become a test case for insurers dealing with the emerging fallout from sports concussions and head trauma claims. The NFL declared former Carolina Panthers defensive back Haruki Nakamura fully and permanently disabled after the August 2013 concussion he received in a preseason game, awarding him monthly benefits.