Davis includes a really great analogy for how to look at the Salary Cap:
The Seahawks as a team are seated on a plane - think of the roster split between first class and coach, with John Schneider and Pete Carroll piloting the aircraft and the coaching staff running the show as the attendants. 18 of the 53 total Seahawks can sit in first-class - and these are the guys that make $2 million or more per year, and the 35 other guys sit in coach and make near league-minimum salaries. The back of the roster fellas sit in the rear by the bathrooms and crying kids, with the loud drone of the engine in their ears.
As Davis posits, you can probably have about nine offensive players and nine defensive players (or so) sitting in First Class so the team has to choose which guys they want for their ever-exclusive Business Class Program. The rest of the 35 guys are just working as hard as they can to earn the right to sit up front and get warm towels, fat leather recline-able seats, and the best in-flight meals. If any of them do earn that right - it just means they're going to be replacing someone that has transferred planes or they'll be bumping someone else out off the plane altogether.