"Yeah, we did meet. … [Tarantino] wanted to start shooting at the end of the year and do rehearsals before that, and I just couldn't do that schedule-wise. That's the only reason [I passed on the project]," said Mortensen.
He added: "It would have been really, really fun to work with [Tarantino]. I think he's really smart and funny."
http://www.hollywoodreporter.com/news/viggo-mortensen-hateful-eight-i-783587