It was stated last year that Sony had asked him and he had already turned down the role.
http://ca.ign.com/articles/2014/11/12/chris-pratt-reportedly-passes-on-uncharted-movie
I'm guessing he had bigger movies lined up (ie. Guardians, Lego, Jurassic World). With rumors of studios wanting him to be the next Indiana Jones why would he be Nathan Drake?
I hope Sony will continue to try and get him, he may change his mind. And I can definitely see him fit the role of Nathan Drake well.







