According to Sega (via Polygon), the upcoming free-to-play massively multiplayer online game will not be out in early 2013 as was previously announced. Its release window has been pushed back to an unconfirmed period.
Sega has not provided details on the reason for the delay at this point in time.
PSO2 was out in Japan in July 2012 for the PC. The game was ported onto the PS Vita in February of this year.