Zach Snyder Returning For "Xerves" Or Not?

It's been reported that Zach Snyder may not be returning to direct "300" prequel, "Xerves". He's reportedly way too busy to return, as right now, he's dealing with "Superman: The Man Of Steel".
While promoting his new film, "Immortals", Mark Cantan, who was the producer of "300" said, "I can't say, I mean, he's got 'Superman.' He's busy. We're busy. I don't think we're going to wait two years. But we'll work together with him and figure out who the filmmaker should be."