Over the course of the season, you probably wonder why television networks do things a certain way. Under the jump, I will attempt to explain some key rules the NFL has showing games on television.
Doubleheader vs. Regional Coverage
You might hear a preview read by James Brown saying, "Doubleheader day on CBS," and one by Curt Menifee saying "Regional coverage on FOX." This means that each Sunday one network has a doubleheader, and the other only shows one game. There is an early afternoon timeslot and a late afternoon timeslot. The network showing the doubleheader has a game in both timeslots. The network with regional coverage only has a game in one timeslot.
Say you are a college student in Boston. The Patriots play early on CBS. The Jets play late, but in the late timeslot, they are showing the Patriots postgame show instead of the Jets game. Are they so Pats obsessed up there that they show a postgame show instead of the Jets? No, it is just CBS has regional coverage that weekend and can only show a game in one timeslot. (This actually happened to me in college, which is how I became so well versed.)
Network
The visiting team determines the network a game is on. CBS shows all afternoon games in which an AFC team is the visiting team. FOX shows all afternoon games in which an NFC team is the visiting team.
The Entire Game of the Local Team Must Be Shown
Say the Jets are playing the early game on CBS. You think you are set because you live in Miami. They are showing the Jets because the Dolphins are playing late on CBS. The Jets are driving it into the red zone down by 4 in the last minute. Then it hits 4:15, and they take you away because the Dolphins game is about to start. That can and does happen.
No Other Game May Be Shown When the Local Team Plays at Home
You know the whole doubleheader vs. regional thing? There are exceptions. The biggest one is when a local team is playing a home game. No other game may be shown at that time. You live in New York. It is a doubleheader Sunday on CBS. The Jets play late. That big Patriots game is early. You can't wait to watch it. Then CBS has an infomercial. Why? The Giants are probably playing at home on FOX in the early slot. That means you are out of luck. No CBS doubleheader for you. The league sometimes makes special exceptions to this rule. For example, tomorrow the Bears play at home early on FOX. You get the Colts-Texans game early on CBS in Chicago, though. This is because CBS has no late games due to its tennis coverage tomorrow. Enforcing this rule would leave you without a CBS game.
Blackout Rule
If the home team does not sell out its game within 72 hours of kickoff, the game is not shown within a 75 mile radius of the stadium. Why? The league does not want people watching at home instead of spending money to go to the stadium. If the stadium is not sold out, you can see the game by buying a ticket. The league frequently makes exceptions.
Secondary Markets
A network must carry all road games when they are considered a secondary market. Television markets within 75 miles of a team's stadium can be claimed as a secondary market by that team. For example, the Patriots' primary market is Boston. Boston must show all games in their entirety. They claim Providence as a secondary market, which means the Providence CBS station has to show all Patriots road games. So if the Jets ever grab a local hero from Providence, his games will not be on local television if the Jets play on the same network on the same timeslot as a Patriots road game. Otherwise local affiliates can show games at their discretion. In 2008, Wisconsin stations showed as many Jets games as they could because Brett Favre meant big ratings. You saw a lot of Titans games in Austin the past few years because University of Texas hero Vince Young played for them.