The salary cap has been a stark reality of the NFL for decades now. We even define the history of the game since its inception as ‘the salary cap era’, which greatly limited teams’ ability to spend on its players, and gave said players greater freedoms to move around and get the best offers for themselves.
It’s made anybody who is more than a casual fan dabble into the financials of the sport as they contemplate whether or not their favorite team can afford to sign one free agent or another. You have to fit 53 players, plus a practice squad, among other expenses, under the cap every year.