A free agent is a player whose contract has expired and is eligible to sign with another team. A restricted free agent is a player for whom another team can make an offer, but his current team is allowed to match that offer. If the current team chooses not to match the offer, it may receive compensation in the form of a draft choice. The NFL awards compensatory picks based on the net loss of restricted free agents. The limit for compensatory picks is four per team.

The supplemental draft is held after the draft and its more like a auction teams bid for players using the following year's draft pick. if you believe a player is 1st round material in the supplemental draft you bid your 1st rd pick from next year and if you win the player you lose the spot you picked that player at for the following year's draft. The NY Giants did this years ago with Dave Brown. They used a 1st Rd pick in the Supplemental Draft to select hom and did not have a 1st RD pick in the regular draft the following season.