UPDATE 9.04pm: SCEA has responded to Richmond's departure with the following statement:
"SCEA can confirm Justin Richmond has left Naughty Dog to pursue other opportunities. The development timeline of Uncharted will not be impacted."
ORIGINAL STORY 8.33pm: Uncharted 4's game director, Justin Richmond, has left Naughty Dog to pursue a career at League of Legends developer Riot Games.
"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."
Richmond had previously served as game director on Uncharted 3: Drake's Deception, and he worked on Uncharted 2's multiplayer. He had been with the company since 2008.
Earlier this month Naughty Dog's creative director - and at least co-director on all of the Uncharted games - Amy Hennig departed from Naughty Dog as well. Initial reports said she was "forced out," but Naughty Dog co-presidents Evan Wells and Christophe Balestra denied this.
It's unclear how Richmond's departure will affect Uncharted 4 going forward. We've requested comment from Naughty Dog and have yet to hear back.