I didn't have the game on when I read this post, then went and watched it and I've got the same question. How was that guard "set" when the ball was snapped?
The guard would be standing, looking at Roethlisberger, then turn around, go into his stance, tap the center and the ball would be snapped immediately. Wouldn't this fall under the same umbrella as a receiver in motion who doesn't come to a full stop before the ball is snapped?
Two other questions:
How did the Tampa defense not time this up? As soon as the guard went into his stance, he tapped the center and the ball was snapped, every time. Someone on the defensive line should have been getting a jump based on that.
From the "We're always the victims" category: If Mason or Thuney were doing this, the rules experts on twitter would have been throwing a fit last night.