Cablevision Systems Corp. has struck a multiyear deal with the National Football League to carry its NFL Network and NFL RedZone channels, adding some of most highly valued sports content to Cablevision's lineup in time for the coming football season.

Financial terms weren't disclosed.

The NFL Network, in a move designed to increase the pressure on those pay-TV distributors holding out, began showing a select number of live games in 2006, mostly on Thursday night. This year, the NFL Network expanded its regular-season schedule and will broadcast 13 games, starting with the Chicago Bears visiting the Green Bay Packers on Sept. 13.

The deal further solidifies the NFL's position as a must-have independent sports network for cable operators—at a time when bigger sports networks like Walt Disney Co. 's ESPN typically command an outsized share of viewers, advertising dollars and subscriber fees.

Sports programming is an attractive asset for broadcasters and their advertisers because it is typically watched or listened to in real time by a loyal base of male fans, who tend to be big consumer spenders but can be hard to reach for advertisers.