NFL's new helmet-hit rule may be tough to enforce

The NFL has been hard at work restructuring its rules this offseason. This includes a new rule that aims to prevent helmet-to-helmet hits. But how exactly will the NFL make sure the rule is enforced?

The NFL has been hard at work restructuring its rules this offseason. This includes a new rule that aims to prevent helmet-to-helmet hits. But how exactly will the NFL make sure the rule is enforced?