Given the salary cap I consider team building an exercise in acquiring stars(big salary cap dollars) and supplementing them with cost effective non-stars(low salary) and rookie deal players.
The salary cap limits how many stars a team can have on its roster over the long term. This also shows the tremendous added value of drafting a star rookie deal player Overall though this key seems to sign players who outperform their contracts.
I do find it interesting that a team may, on purpose, select lesser players in greater quantity than a small number of better players do to their current roster composition and salary cap implications.