What to know about an uncapped year

In 2006, NFL owners were on the verge of losing the salary cap.

Many high-revenue owners resisted continuing with the cap under a revenue-sharing plan that they detested. Still, then-commissioner Paul Tagliabue worked out a deal with the late Gene Upshaw, then the NFLPA executive director, that favored the players but preserved the cap.

Within a year, a majority of the owners felt the 2006 collective bargaining extension was so bad, they couldn't wait to get out of it. They executed an early opt-out of the deal in 2008, eliminating the cap in 2010 and pointing both sides toward a possible lockout in 2011. At 12:01 a.m. Friday morning, the 2010 business season began without a cap and with plenty of uncertainty.

After nearly two decades with a salary cap, general managers, agents and negotiators don't really know how this free-agency period is going to play out. Fans don't know either. To help you get through it, here are the five main things you need to know about this unique period in NFL history.

1. Unrestricted free agency. The big difference is that players must have six seasons of experience in order to become unrestricted free agents (instead of four). That waters down the free-agent pool. The list is slightly more than 220 players, but nearly three-quarters of them are in their 30s. Many won't get jobs. In past years, teams worked behind the scenes at the Indianapolis scouting combine to work out premature deals to make sure they got the top free agents. But there are so few top players this year, little cheating went on in Indianapolis. If a starter is considered someone who started at least eight games, there are only 69 starters to choose from in this free-agent pool. Julius Peppers leads a small group of top defensive ends that includes Kyle Vanden Bosch of the Titans and Aaron Kampman of the Packers. Kampman played out of position last year at linebacker for the Packers and probably will go to a 4-3 team. Karlos Dansby of the Arizona Cardinals is the top linebacker, particularly if Gary Brackett re-signs with the Colts. The top wide receivers are Nate Burleson of the Seahawks, Kevin Walter of the Texans, Antonio Bryant of the Buccaneers and Terrell Owens of the Bills. Cornerback Dunta Robinson of the Texans and safety Darren Sharper of the Saints are the top defensive backs. After that, the list is thin.

2. Restricted free agency. This is the biggest change. Now, free agents with less than six years' experience are restricted free agents. This robs unrestricted free agency from top young players such as Elvis Dumervil, Brandon Marshall, D'Qwell Jackson and DeMeco Ryans. The list started with 212 players but is being whittled down because some players are not receiving offers. There is also the normal restricted free-agent class of players who have three years of experience. A restricted free agent can be signed by another team, but the original team has seven days to match the offer. Teams restrict the movement of these players by assigning a draft-choice value. There are five levels for restricted free agents who have three seasons in the league -- $1.101 million for players with no draft-choice compensation, $1.101 million for the draft level at which the player entered the league, $1.684 million for second-round compensation, $2.396 million for first-round compensation and $3.043 million for first- and third-round choices. The five levels for restricted players with four years of experience are $1.176 million for no draft compensation, $1.176 million for the draft level at which the player entered the league, $1.759 million for second-round compensation, $2.521 million for a first-rounder, $3.168 million for first- and third-round choices. The levels for five-year players are $1.226 million for no draft-choice compensation, $1.226 million for the draft level they entered the league, $1.809 million for a second-round choice, $2.621 million for a first-rounder and $3.268 million for a first- and third-rounder. If a team doesn't match an offer sheet, allowing a restricted free agent to sign with another team, it gets the assigned draft-choice compensation.

3. No cap, no floor. This goes to the motive of the owners. Having a cap kept rich teams from outspending the poor, but the expiring CBA also required teams to spend at least a certain amount on player salaries. That was known as the floor. The number grew to $111 million last season. With the uncapped year, teams can spend as little as they want. After the Kansas City Chiefs cut wide receiver Devard Darling on Wednesday, their payroll dropped to $41 million. The average payroll of a team heading into free agency is less than $85 million. Last year's salary cap started at $123 million but rose to $127 million after an accounting adjustment. In this uncapped year, teams can spend as little or as much as they want.

4. The Final Eight Plan. This is perhaps the most confusing issue of the uncapped year for fans, but the concept is pretty simple. The deeper a team went in the 2009 playoffs, the less it can do in free agency. For example, the final four teams in the playoffs -- the Saints, Colts, Vikings and Jets -- can sign an unrestricted free agent only if they lose a free agent. Don't expect these teams to be in the free-agent bidding. Those four teams have 24 free agents combined, and few of them are starters -- particularly if the Colts re-sign Brackett and the Saints re-sign Sharper. The four teams that lost in the divisional playoff round -- the Cowboys, Ravens, Cardinals and Chargers -- have a limited ability to go into free agency. They can replace a lost starter, but they can also sign one unrestricted free agent with a first-year salary of around $5.5 million. Basically, the top eight teams of 2009 have to take a wait-and-see position on free agency.

5. The potential lockout of 2011. The clock is ticking for a possible lockout by owners in 2011, but football will continue in 2010. Owners are using this uncapped year to test the resolve and unity of the players. The uncapped year also buys owners time to see if they can agree on an acceptable revenue-sharing plan. The next big benchmark of the labor talks could come in May or June, when the Supreme Court rules on the NFL's case against a company called American Needle. In this case involving hats, the NFL is claiming its 32 teams are a single entity and therefore exempt from antitrust laws in exclusive licensing agreements with one company to produce branded hats. If the NFL wins the American Needle case, it could control the CBA talks because it would have the antitrust protection that isn't currently available to it in labor. If the NFL loses, it may be in a different position, ready to work out a deal with the players.

John Clayton, a recipient of the Pro Football Hall of Fame's McCann Award for distinguished reporting, is a senior writer for ESPN.com.