Tristan Wirfs: G or T?

I keep hearing he is capable of playing guard, as well as tackle. And a lot of people, and a few here say he is better suited for the guard spot. I don’t get it. He’s big and very fast with good feet. He is actually more athletic than some of the defensive ends he may face.

So why say he isn’t ready to play tackle over a very average Haeg? He is a physical specimen and strong. His legs are like tree trunks. Quick for someone that size, literally a freak. So why can’t he play tackle immediately?