After an abysmal first half performance, followed by a missed field goal to start the second half it appeared that the Dallas Cowboys had no answers for what the Detroit Lions were doing defensively in their wild card playoff game. The running game was getting stuffed and the pass rush was killing Tony Romo.
That was when the coaches made a smart decision. On the second drive of the second half, Dallas came out in shotgun on first down and went against tendency, passing the ball to DeMarco Murray for seven yards. Then on second and short, a down Dallas usually goes empty backfield, Dallas instead ran the ball and picked up another eight yards and a much needed first down. On the next play Dallas again came out in shotgun, but ran from the formation picking up 15 yards and DeMarco Murray's second longest run of the day.
From there the offense was back. Dallas stayed in shotgun on their next six plays, including a 7-yard touchdown run by Murray that was called back due to holding. The only plays that were not shotgun were the two power runs on 3rd and 4th down at the one-yard line. Dallas scored, and would go on to score the next 17 points in the game.
So what changed? The answer is simple but important. Dallas spread out the field and went against tendency. They forced Detroit's defense to react instead of simply teeing off on the run every first down, and the pass on every shotgun snap. They also went predominantly three-wide, forcing Detroit to play in the nickel. Because Dallas was able to run out of this formation, it put Detroit in a numbers disadvantage, and forced them to guess whether Dallas was going to run or pass.
In my Keys to the Game article I noted that only two teams gained more than 100 yards against Detroit's defense, the Jets and Green Bay. The one thing they had in common was that they played primarily shotgun, and ran out of shotgun a combined 55 carries. By putting Detroit on its heels it forced their defense to react instead of attack.
By going three-wide Dallas forced Detroit to play the pass; which consequently allowed Dallas to run. Once that happened Dallas began dictating to the defense instead of the other way around. It was a simple change, but one that ended up helping Dallas win the game.