Sony has officially confirmed that The Last of Us has been delayed until June 14. Previously the game was set for a May 7 launch but it looks like Naughy Dog wants to perfect the game before release. Here is a quote from Naughty Dog on why The Last of Us has been delayed:

"As a team we pride ourselves on setting a very high quality bar for every aspect of our games – gameplay, story, art, design, technology and more. We want to make sure The Last of Us raises that bar even further – for ourselves, and most importantly, our fans.

As we entered the final phase of development for The Last of Us, we came to realize just how massive Joel and Ellie’s journey is. But instead of cutting corners or compromising our vision, we came to the tough decision that the game deserved a few extra weeks to ensure every detail of The Last of Us was up to Naughty Dog’s internal high standards."