At the end of the NFL season, teams immediately turn their attention to ways to improve their roster the following season. And while the free agency period is a time where they can do so by spending cash, a much cheaper and proven successful route, is selecting the right players in the NFL's Draft.
Thousands of college players become eligible to be promoted from college to the NFL, with each team having a pick in each round, and able to trade those picks for players already on other rosters, with the teams who have the lowest win record from the previous season having the higher selections.
With the teams who have the lower records usually doing so because of poor quarterback play, it's natural for those teams to be looking for an upgrade at the position - with the draft usually providing the best chance to do just that.