Naughty Dog doesn't have 2 full fledged teams, they have 1, their meain team that is working on Uncharted 4, and then a small team (probably 30-40 people) working on pre-production for The Last of Us 2, so stating that they have two teams is misleading. 


They only have the manpower to be in full production 1 game at the time. 

I know :)

But it probably went something like this. I am just throwing numbers around. I don't know shit.


2009 - Uncharted 2: Among Thieves 

20% of the team began pre-production on The Last of Us
80% began began working on Uncharted 3. Naughty Dog hires 20%, so now that are at 100% again and they begin full-production (quite easy, they already have all the assets, story, characters etc.)

2011 - Uncharted 3: Drake's Deception

20% of the team began pre-production on Uncharted 4
80% joins the other 20% and begins full-production on The Last of Us.

2013 - The Last of Us

20% Begins to work/finish Left Behind.
80% Joins the other 20% and begins full-production on Uncharted 4

2014 - Left Behind 

20% Begins pre-production on The Last of Us 2.



It was during the marketing campaign for The Last of Us he mentioned that they worked on multiple projects, that would fit what I say. The Last of Us, Left Behind and Uncharted 4: A Thief's End.