One of the main issues separating the National Football League Players Association and NFL management is free agency.

Currently, if a player's contract has expired, his team has the right to match another team's offer -- also known as the right of first refusal. If the new team signs the player, it must compensate the player's original team with draft choices, the number and round of which are determined by the amount of money for which the player signs and the player's experience level.

For example, compensation for a three-year veteran earning $280,000 or more is two No. 1 draft choices; for a three-year veteran earning between $230,000 and $280,000, it is a No. 1 and No. 2; for a three-year veteran earning $180,000 to $230,000, it is a No. 1 and No. 3; and for a three-year veteran earning between $140,000 and $180,000, it's a No. 1.

Compensation for a 10-year veteran earning $350,000 or more is two No. 1 picks; $300,000 to $350,000 a No. 1 and No. 2; $250,000 to $300,000 a No. 1 and No. 3; $210,000 to $250,000 a No. 1.

The NFLPA wants a system under which players with four years in the league who play out their options can be signed by any other team without the original team maintaining the right of first refusal and without the signing team being required to provide compensation. The NFLPA wants players with less than four years in the league to be able to move with the original team maintaining the right of first refusal, but without the signing team required to provide compensation.

The NFL owners want a system under which the clubs would maintain the right of refusal for all free agents, with a compensation schedule more liberal than the one currently in place.

Each of the major sports has its own system.

The NBA's free agent system basically revolves around the right of first refusal.

If a player plays out his option, he is free to negotiate with any other club. If he agrees to terms with a new team, he presents his original team with an offer sheet outlining those terms. The original team has 15 days to match the offer. If it does, the original team retains the player. If it chooses not to, the player moves to the new team without compensation.

The latter situation rarely occurs. Teams often match an offer sheet without any intention of keeping the player, then trade him, thus receiving some measure of compensation. Occasionally, a team wishing to sign a free agent offers his original team an inducement for waiving its right of first refusal.

In the National Hockey League, free agents fall into one of three classifications:

Those under age 24, who haven't played five years professionally.

Those between ages 24 and 31, who have played five years or more professionally.

Those age 31 or older.

If a player of the first type signs with a new team, the player's original team must be compensated. The two teams are given the opportunity to decide a mutually agreeable form of compensation. If they are unable to reach an agreement, the issue is settled through binding arbitration with each team making an offer and the arbitrator choosing one. There is no right of first refusal.

When a player of the second type becomes a free agent, his original team must make a minimum contract offer of $110,000 in order to maintain compensation rights. If the player is age 24 or 25, his original team must offer a contract with a 15-percent salary increase in order to maintain the right of first refusal. There is no right of first refusal when players are older than 25.

When a player of the third type becomes a free agent, his original team must offer him a contract with a 15-percent salary increase in order to maintain compensation rights.

In Major League Baseball, at the conclusion of each season, all the players on the teams' rosters and disabled lists as of Aug. 31 are classified based on their statistics from the just-concluded season and the season before. The top 30 percent of the players at each position are designated Type A. The next 20 percent of the players at each position are designated Type B. The next 10 percent of the players at each position are designated Type C. The lower 40 percent of the players at each position are given no designation.

In order to be eligible for free agency, a player must have six years of major league service and not have been through the free agency procedure within the last five years, provided he was a classified player at the time. Then, within 15 days after the World Series, the player must notify the Major League Baseball Players Association that he wants to become a free agent. At the conclusion of that 15-day period, any player who has declared himself a free agent may negotiate with any team.

By Dec. 7, the player's original club must offer him the opportunity to have his salary determined through binding arbitration, with the player and the original team making suggestions and the arbitrator choosing one. If the player's original club does not do so, it becomes ineligible to sign the player until May 1.

If the player accepts his original club's offer to go to abitration (and he must do so by Dec. 19), he is not subject to the five-year repeater rule described above. If the player rejects his club's offer to go to arbitration, the club has until Jan. 9 to sign him. If it does not do so, it may not do so until May 1.