N.F.L. teams are completing their depth charts, but for the most part they know who will be the starting quarterback, the most important slot.
The starter appears in the television ads and dates the supermodel or pop star. Meanwhile, the second- and third-stringers hold clipboards in relative obscurity.
But once the season begins in earnest, real life will start to intrude. Starting quarterbacks will be injured or perform poorly. The big name that was written with such confidence on the team sheet often has to be replaced by someone a trifle less famous.
Last season, only half of the 32 N.