Sprint (NYSE: S) Nextel’s partnership with the National Football League, which is valued at almost $500 million over five years, is finally kicking into second gear. For the remaining eight weeks of the season the carrier will be broadcasting games that were previously only available on the NFL Network. Beginning with Thursday’s game between the Cleveland Browns and the Denver Broncos, Sprint mobile phones will have access to one game each week. The NFL Network is still only available in about 40 percent of American households, so it’s a big grab for Sprint and a way to clearly differentiate its offering from competitors The games will be offered as part of the carrier’s $15 a month NFL Mobile Live service, which has been the most popular application ever for the struggling company. And yet despite its popularity, Sprint is paying dearly each year—$50 million – to be the NFL’s exclusive wireless sponsor, WSJ reports.  It’s tough to see how the carrier could recoup those costs, particularly since the NFL package alone probably isn’t enough to lure many customers away from competitors. Release.