NFL players, historically losers in power struggles with team owners, can retake control of the kneeling-protest issue if they use social media to connect with the public.
Much of the discussion about "Take a Knee" has overlooked the issues of justice and social exclusion, and especially environmental matters. That's something to think about during the Super Bowl.
The main reason owners and athletes stay away from mixing politics and sport is that it allows them to sell their product more easily. In doing so, pro sports conforms to classic capitalist ideology.