Photographing the quarterbacks in a football game is imperative. One of them, after all, could have a banner day or make the play of the game.
Some recurring problems exist, however, in trying to get good photographs of each QB. Bleachers, lights posts, and vehicles in the background are distracting features that need to be avoided at all costs. Separating the subject from the background is necessary but is sometimes difficult. This is especially true for wildlife photography because the subjects often blend into their backgrounds to keep them safe from predators. The same is somewhat true for QBs: they can blend into distracting backgrounds as their predators(opponents) try to sack them!
Shooting wide open with a large f-stop (small number) is a good first step in separating a subject from its background. What happens is the focus is one the subject but the background is blurred out of focus. The depth of field is shallow in this case and helps in separating the subject from its background.
Additionally, other players or referees can move between the QB and our camera. Keeping the QB separated from his opponents is not only the task of the linemen, but it is also the task of the sports photographer. My approach is to take some time during each game to focus entirely on the QB. Sometimes it works well and sometimes, well, I struggle. Lack of good light or distracting and overpowering light can lead to problems as well.
Focus on the subject and photograph the QB. This approach can tell an important part of the game’s story. Give it a try: focus on the quarterback!