Thanks to the success of Robert Griffin III, Russell Wilson and Colin Kaepernick, more teams will look to implement the pistol offense and even the zone read option system. Each of these quarterbacks had success early in his career.

Kaepernick, obviously, has a chance to prove that a running quarterback can win in the NFL. But before the copycat league starts, well, copying their success, they have to know this: These quarterbacks succeeded because they can run and pass. No quarterback who only runs and can't pass can duplicate their success. That's why it'll be difficult for a lot of teams to run the zone read (but just about any quarterback can use the pistol, which is just an abbreviated form of the shotgun).

The reason Kaepernick will play Sunday is he beat Green Bay with his legs. Then he beat Atlanta with his arm -- and the threat of his legs. Griffin can, and has, done the same. So, too, has Wilson.

And it's why Tim Tebow remains a backup and always will. If you can't pass, you are not a threat to consistently hurt a defense. It's why Michael Vick remains inconsistent -- and will remain so if he sticks around in Chip Kelly's offense in Philadelphia.

The NFL is better because of players such as these dual-threat quarterbacks. The pistol formation and the zone read game are a great addition and will be fun to watch grow. But if you want other teams to run it, all they have to do is find a quarterback who can run and pass equally well. Those who do have such a player know how far you can go.

- John Keim