We love sport, and sport don't get much bigger than the NFL. Although franchises aren't publicly listed, there are plenty of investment opportunities in our nation's favorite sport to tackle. Strap those helmets on, brush yourself down, and prepare for the next play with these top stocks linked to the NFL season - including some of the biggest long-term sponsors of the national game. Remember, make sure you read the playbook before stepping out on the field (as in, always research stuff before placing a trade). DYOR.