More photos » by Ross D. Franklin - AP

Arizona had trouble rushing against Arizona. Alan Branch (78) is on the back just as he receives the hand off.

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With the stages of execution described, we can now explore the matchups that will determine if that execution is successful. The many individual matchups that must be won explain why teams do not break long runs on every attempt. In a way, the stages help determine the -1 to 2 yards, 0 to 5 yards, and 5 to n yards of the run.

Chris Spencer, Max Unger and Steve Vallos/Mansfield Wrotto versus Bryan Robinson, Darnell Dockett, Alan Branch and Gabe Watson: Dockett is the most talented of the group, but as a one-gap player, I do not think he is likely to play nose against a two tight end front. If Dockett is in, the play will turn less on if Seattle can move Dockett, Unger and Spencer should be able to, but more if Dockett can tie up Spencer or, more likely, break Unger's single block and get back into the play. When Dockett is in, Julius Jones should be cutting back inside to help neutralize his speed and perhaps take advantage of over-pursuit.

Robinson is the starter and he rotates with Branch. This is the matchup that will do much to determine if Seattle can run. A giant among giants, Branch was once dubbed a top ten overall selection, but very real concerns about his effort dropped him into the second round. He hasn't done much for Arizona since being drafted, but he's only 24. Branch has begun to establish himself this season.

Whoever the nose, and Arizona sometimes plays a double nose and a 2-4 in nickel situations, the Cardinals have a young, powerful and huge defensive line that is difficult to move. Indianapolis had some success running delays to the outside. Whatever the play call, outside is the destination.

Seattle's interior may wish only to battle to a stalemate. Branch and Robinson move well off the line and both are athletic within their space. The two make it difficult to disengage and move into the second level. Branch's power off threatens an interior collapse on every snap and rushers can have trouble receiving the hand off without defenders in their face.

That is why you draft Chris Spencer. Once a upon a time, he could move out and wall off nose tackles with ease. There wasn't a nose tackle in football short of Vince Wilfork I would bet against Spencer. But it's been a long time since we've seen that power, even as his technique has begun to catch up with his athleticism. Seattle's mishmash of guards matter, but a fraction as much as Spencer. If Spencer can stagger the nose off the snap, Unger or Vallos can exploit the momentum enough for Spencer to release. If he can't, Jones will miss essential second level blocking. If Spencer cannot even control Branch or Robinson off the snap, Jones will be facing a pile upon receiving the hand off.