Every year, NFL teams hope to supplement their existing rosters in the NFL Draft, which allows them to pick up some of the best amateur football talent in the country — but the market is not totally free.

Over the course of the seven rounds spanning three days (Thursday, Friday, and Saturday), teams can draft players who have been out of “high school for at least three years and must have used up their college eligibility before the start of the next college football season,” according to the league’s official website. Additionally, players who do not meet those requirements may request special approval from the NFL to be draft-eligible.