Source: Craig Calcaterra, NBC Sports 
My guess is that this begins the Wilin Rosario: first baseman experiment in earnest. For Mr. Rosario is a truly gifted hitter and a truly not-very-good defensive catcher. He’s a future Mike Napoli. Except Napoli used to catch fairly decently if I remember correctly.
Obviously the simple solution here would be to create some sort of Ruiz-Rosario cybog/golem thing, but the Rockies are a conservative organization and have never been accused of having that sort of brilliant vision.