You may know that DirecTV is the sole provider of the NFL Sunday Ticket service, that allows subscribers to watch any NFL game they wish. But you may not have suspected just how important that service is to DirecTV’s financial fortunes.

Any doubt about that was eliminated today when it was revealed that AT&T can opt out of its 48 billion dollar deal to acquire DirecTV IF DirecTV does not retain the rights to provide the Sunday Ticket.

The NFL’s Sunday Ticket lets subscribers of the satellite broadcaster access every NFL game on Sunday afternoon for as much as $250 a season. The current deal, which expires at the end of the upcoming season, costs DirecTV about $1 billion a season.

About 2 million of DirecTV’s 20 million subscribers pay extra for the NFL Sunday Ticket package, or about $1.32 billion from those customers each year.

The NFL and DirecTV have been trying to hammer out a new contract for several months.

The NFL certainly is looking for more money from DirecTV for Sunday Ticket. Some industry observers have anticipated that the annual price tag could rise 40 percent to $1.4 billion next season followed by annual increases of 4 percent.

Just imagine how NFL owners have to be salivating about their next meeting with DirecTV. Their acceptance of a Sunday Ticket agreement extension means whether or not DirecTV shareholders will receive 48 billion dollars. It’s safe to say DirecTV is in a bad negotiating position.