Phil Harrison will step down from his position at Sony at the end of the month in order to "tackle new challenges in the video game industry."

Although details of what exactly Harrison plans to do post-Sony are not confirmed, Sony said current game chief Kazuo Hirai will assume the management of SCE's software development group in addition to his current duties.

"It is sad to see him departing from SCE, but I wish to express my gratitude for his many invaluable contributions and also wish Phil the very best of luck in his future endeavors," Hirai said in a statement.

Some news outlets, including Gamesindustry.biz, are speculating that Harrison may be leaving Sony to join Atari, and that the move could be out of frustration that his former employer was slow to take advantage of social gaming.

The BBC quoted a statement he made at a recent private lunch: "Our Japanese colleagues said that there is no such thing as social gaming in Japan -- people do not play games on the same sofa together in each other's homes. It will never happen...and then out comes the Wii."

Harrison was involved in the launch teams for all of the PlayStation consoles, and had served in a number of roles over his tenure. He has held management positions in both the company's European and North American divisions, most recently as president of SCE Worldwide Studios.