After rumors last week, Team Ico director Fumito Ueda has definitely left Sony, according to Gamasutra. Sony confirmed that Ueda is no longer an employee, but will continue to work on his current project, The Last Guardian, as an independent contractor.
Ueda and his team have only produced two games in the past decade, Ico and Shadow of the Collossus, both of which were originally released on the PS2. While neither game was a breakout success financially, both have been declared modern classics by many critics and developers.
Still, the fact that The Last Guardian has been in development since before 2009, probably has a lot to do with why he's leaving, regardless of the circumstance.