without having watched a ton of Braves games this year, I'd have to say he's been lucky there too. His defense is terrible. If he hasn't put it on display yet, trust me he will. I used to cringe any time a ball was hit his way.
He's mainly been serviceable because he played a bunch of 1B while Freeman was out. He's been pretty bad at 3B defensively lately in particular. But given that he's a terrible defender as you mention, not surprising.
Still, he's a solid half of a platoon with Juan. He's clearly not going to hit .350 all year, but he should be able to hit close to .300 against lefties, which is what we need from him.