This is a great description of zone running. I was going to comment on Pierce with clips from Seth Payne's review of the game on Youtube, but for some reason it was taken down (Seth may have hit a wrong button, I love the guy but his technological struggles are still a work in progress) if the video comes back I'll try to add it into this post or make a new one.
One play (among many) stood out to me, Pierce was running to the right side of the line in outside zone when a cutback seam opened right down the backside of the line into the center of the field. I describe the steps in zone running as "One Mississippi... Two Mississippi...
GO!!!!!" In this particular play instead of the immediate cut back step, Pierce took 4-5 extra steps where the
GO! should have been that rounded his path right into the back of the blocking OLmen. It's incredibly frustrating to see a 5-7 yard gain turn in to a no-gain blunder, particularly when the blocking worked out with a 2nd string G and T.
I hate to be negative during such a great time to be a Texans fan, but my prediction is that Pierce isn't going to make the roster.
Edit: Here we go the video's back up it's the run at 2:14 into the video.