Fox Sports National NetworkSources tell Bloomberg that News Corp is working to obtain rights from pay TV outlets and sports leagues to launch a national cable network that could begin service by year’s end. No final decision has been made, but the plan would involve converting the company’s action sports network Fuel (36 million subs) into a new national offering, which would compete against fellow cablers Disney/ABC’s ESPN, Comcast’s new NBC Sports Network and the CBS Sports Network. Like those entities, News Corp is attracted to the juicy affiliate fees a national sports network can command; SNL Kagan estimates ESPN will collect $5.06 per subscriber each month in 2012, more than any other cable channel. Other ESPN channels — including ESPN Classic, ESPN2 and ESPNews — collectively generate an additional $4.13 per sub per month. By contrast, Fuel collects about 15 cents per sub each month. Additional money would come in handy to offset the growing costs of sports rights these days, and it might not be a coincidence that this news comes a day after the Dodgers chose new owners who will be very interested in selling TV rights to the team’s games in the nation’s second-largest TV market  — it’s a price tag that could go as high as $3 billion (or even $4 billion if you believe the LA Times). Fox Sports is the current owner of Dodgers rights but will need the extra cash in a likely bidding war.