The most important position in the NFL is often the most vulnerable.
Just look at the Dallas Cowboys, who have imploded since quarterback Tony Romo went down with a broken collarbone in Week 2.
By the time Romo returns, it might be too late for the Cowboys.
That said, Dallas is hardly the only team to skimp on a backup quarterback and wind up paying a heavy price. Much rarer are teams such as Pittsburgh, which wisely had both Michael Vick and Landry Jones waiting in reserve when Ben Roethlisberger was injured early in the season. They kept the Steelers afloat, going 2-2 while Big Ben was out.
The Cowboys haven't won since Romo was injured in a victory over at...