[Goldenfleece]

Players who apply for the supplemental draft are usually guys who were planning to play another year but for some reason won't be able to. Sometimes there are players who are now academically ineligible to play or got kicked off the team for behavior or whatever. Other times, the reasons are more benign. For example, Texas fullback Ahmard Hall had been serving with the Marines for four years, but technically he had a year of college eligibility left, so he had to submit certain paperwork before a deadline to declare for the regular draft. He didn't know about the paperwork, missed the deadline, and here he is.

Teams put in bids for players (i.e. first round, second round), and if multiple teams put in the same bid, the team who was picked earlier in this year's draft gets the player. A team with a successful bid gives up a pick in next year's draft equivalent to whatever round their bid was for. There are usually only a handful of players available, and teams are free to choose not to participate.