If you want to learn about photographing US gridiron football in particular and field sports in general, you'll find valuable hidden lessons on the Sports Illustrated web site, especially Peter King's Monday Morning Quarterback.
Many of the action photos that illustrate King's Monday morning column have the EXIF intact and can be read by those who have EXIF readers installed in their web browsers. One unsurprising pattern among those images is the frequent use of the Canon 400mm f/2.8 IS lens. But, it's interesting to note that not all photographers used the lens wide open
A check of the web site showed two daytime examples that were stopped down, one to f/4.0 and one to f/3.5.
Night images such as this one were more likely to have the lens used wide open.
EXIF can't reveal why or how specific exposure settings were selected, but study of the images and time of day can help deliver insight into the photographer's decisions.
The EXIF also shows the near universal use of the 1D-X. The 1D-X and 400mm f/2.8 IS is a US $18,000 combination of lens and camera so it should produce good images, but the equipment still needs to be pointed in the right direction at the right time and the shutter button does not push itself. The images linked above always will come as much from technique and experience as from equipment.
