MLG struck the deal without a stockholders' meeting and the sale has upset some investors, according to eSports Observer.

DiGiovanni and Mike Sepso founded MLG in 2002, and throughout the years it's regularly hosted professional gaming tournaments, broken into the streaming business, and helped bring eSports to television and the mainstream. In 2014, MLG opened the United States' first professional gaming arena in Ohio. It planned to open another eSports arena in China by 2017.

MLG's relevance has waned in recent years and in October, it lost the hosting rights to the Call of Duty World League's Pro Division to the ESL. Sepso himself joined Activision that same month as Senior Vice President of its new eSports division, overseeing pro franchises including StarCraft, World of Warcraft, Call of Duty, Heroes of the Storm and Hearthstone.

[Image credit: Flickr/Colin Taber]