I would think that when you try to collapse the pocket quicker than the play-action is allowed to develop, this would do the job. In the act of collapsing the pocket, I would think we'd "contain" rush which would allow one of the lineman to quickly shed if the RB gets a ball and tries to exploit a lane.
With the Zone Blocking Scheme with the running flow going one way and the QB roll out the opposite direction, there's no pocket to collapse.
The backside end man (on the side of the roll-out) needs to stay home; otherwise, the Qb has all the time to set up and throw.
But if he stays home, and the offense runs the ball, the D has one fewer defender in pursuit.
Even if the defense plays well, it's taxing because of the built-in element of the scheme.
It can be defended; but just like how Brady is so smooth out of the Pats scheme, the Texans scheme is also difficult to defend due to execution.
If you've seen some Texans games where they show the view from the endzone; it's impossible (or very difficult) for the D to tell whether it's a run play going to the left or a pass play going to the right.
The PA from power blocking doesn't give the same elements.
In the meantime, Schaub's faked hand-off to the RB is superb, almost all of the times.
They show you the end zone view and you can't tell until he pulls the ball out of the RB's belly.
This, combined with the action of the O-line and the different pass patterns make it more difficult for the defense.
Even teams in the same division find it a task to defend.
Just like what the Pats do on the offense is also difficult to defend.
The guys on the field just need to execute.
We're talking about two very good teams here.
The one that shows up will win, unless a prevalent luck supports one side more than the other.
I hope this game becomes a classic that fans from both Sides will remember;
Knowing that the Texans have never won anything, of course!