Well, in that case, Zim's already outdone him. Rendon was drafted in June, too. Just like Harper, his play will let you know when he's ready.
My point was that Zimmerman made it within months. Rendon obviously can't move that fast, since that timeline has passed.
Im just trying to say, in reponse to you saying you'd be surprised to see him called up at all next year, come next September he'll have more pro experience than Zimmerman when he was called up. So I don't think it's such a stretch to expect to see him next year.
With a big league contract, a full minor league season(which come the beginning of September, the season will be finished) ... Im fairly certain we will see Rendon at the big league level next year. I think his role(whether he's inserted into the starting lineup every day, or spot starts) will be determined by where the team is at(and of course, his own success during the season). If we're out of everything, I think he's playing every day. If we're contending, he may just be up for a couple starts, pinch hits - just get some experience of what its like.