BAMTech plans to launch a League of Legends streaming service with apps for smartphones, PCs and "other devices," and will also handle distribution on existing streaming portals like Twitch and YouTube Gaming. The deal goes a way to explaining the rumor that ESPN was set to invest hundreds of millions to pick up the game's broadcast rights. While the deal appears to be about streaming, rather than broadcasting, ESPN is owned by Disney, and oh-so-coincidentally is launching a streaming service ready for sports that don't air on its traditional cable channels.

League of Legends is a giant in the world of eSports, with individual tournaments watched by tens of millions worldwide. Its popularity has led to Riot Games (which makes no other video games) bringing in over $1 billion in revenues per year. BAMTech and Riot will aim to make (even more) money on the deal through advertising and sponsorship, which the streaming company will oversee.

The deal is akin to videogame publishing, in so much as the $300 million is an advance, rather than a direct payment. Initial revenue generated will go to BAMTech, in order to cover its investment, but The Wall Street Journal says that takings beyond that will be shared with Riot Games at an unspecified rate.

BAMTech, previously part of Major League Baseball's MLB Advanced Media (MLBAM), was spun out into its own company earlier this year. MLBAM still owns a majority share in the company, Disney acquired around a third in a $1 billion deal and the National Hockey League also has a stake.

Update: In case you're wondering, Riot director of eSports Whalen Rozelle confirmed on Reddit that "The current experience we have today is and will continue to be free." He also said the deal could be worth more than $300 million if the partnership goes well, as the broadcasts push for more partners and sponsorship.