9:28 remaining in the 4th quarter

Seahawks down 21-0

Pittsburgh ball, 1st and 10

The Steelers are in a heavy formation: I backs, two tight ends right and a single wide receiver (not pictured). Top (left to right): Marvel Smith, Alan Faneca, Sean Mahan, Kendall Simmons, Willie Colon, Heath Miller and Matt Spaeth. Ben Roethlisberger. Carey Davis. Willie Parker.

Seattle features a standard 4-3, with the linebackers shaded left and a heavy personnel package. Ellis Wyms at left defensive end, Chuck Darby at left defensive tackle, Rocky Bernard at right defensive tackle and Baraka Atkins at right defensive end. Brian Russell is walked up and assigned the offense's left "C" gap. Julian Peterson is playing a classic strongside linebacker, controlling the offense's left right "C" gap, playing opposite the two tight ends.

The Steelers send Spaeth in motion left.

Seattle moves Russell slightly closer to the line. Lofa Tatupu moves from left-left of center to left of center. Peterson moves up into a neutral left linebacker position.

The play starts: Spaeth runs up and engages Russell, Russell is neutralized. Davis moves into the left "B" gap, drawing Leroy Hill and Lofa Tatupu. Ellis Wyms gets push on Smith, moving him back and to the left. Faneca gets under Darby's pads and moves him strong left. Peterson sprints down into the now gaping left "A" gap. Mahan and Simmons double Bernard, but Bernard is able to hold ground. Atkins holds ground against Colon and Miller, but is able to move ever so slightly left. Trufant (not pictured) keeps outside containment on the left side.

1 second in: Russell, Wyms, Darby and Hill are all effectively neutralized. Darby has been turned so that his back faces the sideline. Peterson and Bernard have effectively plugged the gaping left "A" gap, but the required shift has opened a cutback lane at the right "B" gap. Tatupu disengages the pileup left and begins to run back towards the approximately 10 yard swath of open field right between Parker and Deon Grant (not pictured). Atkins edges in on Colon - this is vital.

2 seconds in: Atkins extends a ripped arm and hooks Parker. The tiny wonder chugs his legs, extending the play a couple yards, but he's not escaping.

3 seconds in: Atkins wraps, Grant puts a cap on the play, but Parker gains 7. Tatupu Stands feet away, but is not involved in the tackle. Two seconds later, Darby disengages from Faneca and surveys the product of his failure.

Keys

1. Darby is single blocked out of the play, forcing Peterson to abandon the right "B" gap and plug the gaping left "A" gap. This is the type of run blocking domination that earns Faneca his reputation.

2. Tatupu over-pursues, keying the fullback but missing the cutback. He should have either plugged the left "A" gap instead of Peterson or tracked the rusher.

3. Bernard withstands the double team, keeping the left "C" gap narrow.

4. Atkins withstands the double team and is able to move to the inside shoulder of Colon.

5. Parker is able to be arm tackled. Parker is a pretty good back, but if that's Steven Jackson or Adrian Peterson, you can be pretty sure they would have been able to blow through Atkins' arm tackle. With much of the Seahawks defense pinned to the line and free safety Brian Russell caged by Spaeth, had Parker hit the second level with a head of steam instead of a defensive end in tow, this could have been a 70 rather than 7 yard rush.