The Seahawks have this little thing to contend with called a salary cap, just like the other 31 teams in the league. The cap is a simple concept. Each team is allowed to spend the same amount of money on its players. This promotes parity, unless you’re in New England or Cleveland (up until this year, that is).
So the salary cap determines just how much money the Seahawks – and every other team – can spend in any given year. No team can spend more than the cap in any given year. This is why you’ll often see multi-year contracts set at different dollar amounts for different seasons.