"I have in fact made the decision to leave Naughty Dog," Richmond told IGN. " I love the company and the people and know that they will continue to create awesome games going forward. On a happier note, after careful consideration and exploration I have joined Riot Games. There is some really innovative stuff going on here that I can't wait to be a part of."
This news comes shortly after creative director Amy Hennig's departure from Naughty Dog earlier this month.
Sony Worldwide Studios' has been having a rough month, with numerous layoffs and other departures across the company in March, 2014.