The photographers basically start drifting on to the field about an hour before kickoff. Mostly we get stock background shots, candids from warm-ups, and some photographers are there specifically for the purposes of photographing prospects and visitors. It all depends on the assignment, but all of us have to navigate this mess throughout the game.
Sometimes you get really good candid shots before the game. You also get to see the faces and how the team’s individual and group attitudes are.