Key stat: DeMarco Murray + 100 = Wins

The Cowboys are 6-0 when running back DeMarco Murray gains 100 yards. And they're 8-0 when he has 20 carries or more in a game.

No more evidence is needed to understand why the Cowboys must have a good running game. If -- and this is a big one -- Murray can stay healthy, then he'll give Dallas the running game it needs. Murray has missed nine of 32 games in his first two seasons.

The Cowboys need him because he makes the offense considerably better. When he's running well, Murray forces teams to play with an extra defender near the line of scrimmage, which opens the passing game and takes pressure off Tony Romo.

Now, it's not as simple as giving Murray the ball the first 20 plays. It's about being persistent with the running game and giving it a chance to work -- even if it starts slowly.

If Murray starts 14 games this season, the Cowboys will have the running game they need and they'll make the playoffs.