Norton didn't pick up on it there. But he grips the ball with whatever pitch he is going to throw before it gets to the glove. It was very obvious on the change up he just threw.
Also, he is digging from the windup on his breaking ball, meaning it is obvious he is changing his grip from a normal fastball.
Maybe the Braves aren't picking up on it, but someone mentioned on here that maybe that is why he has been having trouble with men on base. Getting away with it today so far (through 5), but I think that this should be addressed. Watch for it.