In
American/
Canadian professional
sports, the entry draft is the way top-level (
major league) franchises claim the rights to amateur players.
Eligibility rules for the draft vary by sport; for example, baseball players may either be selected in the June after their senior year of high school or following their junior or senior years of college, while in American football, at least three football seasons must have passed since their high school graduation before they are selected in an April draft. The duration of the team's rights to the player while a contract is not signed also varies by sport; in hockey, a player drafted out of junior hockey at roughly high-school age who chooses to attend college remains property of that professional team throughout his college career. Compare this to baseball, where rights usually only last one year, but are terminated immediately if the player chooses to attend college (if drafted out of high school) or to return to college (if drafted as a junior).
Major League Baseball and the NFL order player selections in a straight worst-to-first order by round; the worst team from the previous season picks first, then the second-worst, then third-worst, etc., all the way down to the previous season's champion, after which the cycle restarts for another round of the draft. The NHL and NBA use a variation on this, called the lottery, where the worst few teams are selected in a semi-random order (e.g. the worst team may have its name on 10 balls in the bin, down to the 5th-worst only having 1, and balls are drawn out of the bin until each team has a place in the order), to prevent teams close to last place from tanking late in the season to go for the #1 pick.
Baseball does not allow teams to trade draft selections; all three others do.