The National Football League's 2010 free agency period is not even half over, with action to continue into mid-June. For approximately 150 players on the market, however, the rules are about to change considerably

Of the 531 players who became "without contract" on midnight of March 5, 216 fell into the restricted free agent category. That group was larger than ever before, and chock full of talented players in the prime of their careers, because the final year of the current CBA called for players to need six seasons of accrued credit, not four, in order to become unrestricted free agents.

That former category of free agents is aptly named, because several aspects of restricted free agency make it more difficult for players to sign with new teams. For one, a player's original team retains the right to match any contract offer he may receive. And, even more significantly, signing a restricted free agent away from another team often requires the new team to send back draft-pick compensation. All a player's original team has to do to have these options available is extend a tender offer to the potential free agent just before the opening of the market.

Still, it is a form of free agency, and it has given those 216 players roughly a month-and-a-half to explore the possibility of signing with a new team. In nine days, however, that will no longer be true.

Restricted free agents have until Wednesday, April 14, to negotiate with other teams. After that date, any remaining unsigned restricted free agents may only negotiate with their original teams. The majority of restricted free agents end up re-signing by simply accepting that one-year tender offer, whether they choose to do so before or after next week's deadline.

That's a significant date on the NFL's offseason calendar, then. But will it have a significant effect on free agency this year?

Perhaps not, because the truth of the matters is that there has been almost no team-to-team movement among that original pool of 216 players. A percentage of those 216, though well below half, have already chosen to re-sign with their original teams. That was true last week of Tampa Bay Buccaneers wide receiver Mark Bradley, and it is an avenue already taken by such notable NFL players as San Diego RB Darren Sproles, Carolina QB Matt Moore, Philadelphia WR Jason Avant, Arizona WR Steve Breaston, Kansas City LB Derrick Johnson, Houston LB DeMeco Ryans, Philadelphia CB Ellis Hobbs and Green Bay S Nick Collins.

Only one player who became a restricted free agent on March 5 has signed with another team to this point. Former New Orleans running back Mike Bell jumped from New Orleans to Philadelphia, but even that was not terribly surprising. By tendering Bell at a level that retained a right-of-first-refusal but did not require any draft-pick compensation, the Saints left the door a little wider open for the tailback to leave. Bell became an Eagle when the Saints declined to match Philly's offer.

The NFL's own free agency tracker lists several dozen other players who have switched teams despite being labeled as restricted free agents (RFA). However, all of those players, with the exception of Bell, were really just potential restricted free agents. Many, such as Indianapolis WR Hank Baskett or St. Louis cornerback Jonathan Wade, did not actually receive tender offers from their original clubs and thus were free to sign with any team.

However, one other restricted free agent, former San Diego backup quarterback Charlie Whitehurst, also has a new address, even though he was tendered at a level that required a third-round pick in return. When Seattle showed interest, the two teams instead worked out a sign-and-trade, with the Seahawks sending over a third-round pick in next year's draft instead. Seattle also had to swap second-round picks in this year's draft, moving from #40 down to #60. Such maneuvering was necessary in part because the Seahawks had previously traded their 2010 third-round pick, and the rules of restricted free agency require the signing team to still have the indicated picks in this year's draft.

In fact, that is the underlying reason behind the mid-April deadline for restricted free agents: The matter has to be resolved before the draft. The system allows teams a week to decide whether or not to match a deal; any signings after next Wednesday would leave less than a week before the 2010 draft.

So it remains unlikely that the next nine days will feature a flurry of action from among the remaining restricted free agents. Much more likely is an increase in the pace of the remaining players in this category re-signing with their original teams.

With that deadline approaching, let's check in again with what the free agents from Tampa Bay's 2009 roster have done so far on the open market.

Below are the five players from the Bucs' 2009 squad who became unrestricted free agents when their prior contracts expired on March 5. As the free agency period continues and these players either sign with other teams or return to the Buccaneers, the chart will be updated with their developments.

Three Buccaneers also became free agents when they were released just prior to the start of free agency. Though they were not originally slated to become unrestricted free agents this spring, their releases put them in the same category, with the same freedom to negotiate with any team, including the Buccaneers.

Also, the Bucs essentially increased their list of unrestricted free agents by four more when they chose not to extend tender offers to four players who could have become restricted free agents (more on that category below). Because no offer was extended, these players hit the open market on March 5 like those above, free to sign with any team.

There is a significant difference between restricted and unrestricted free agency, as discussed above. Unrestricted free agents may negotiate and sign with any team, and their previous teams receive no compensation, nor do they have a right of first refusal.

In the 17 previous years of the current free agency system, players became unrestricted free agents when they accrued four seasons of free agency credit and their contracts expired. However, as mentioned above, players must have accrued six seasons before they could become unrestricted free agents in 2010. All players who have three to five years of credit and expiring contracts become restricted free agents as long as their original teams extend a one-year tender offer before the start of free agency.

The Buccaneers extended offers to six of the nine players who were eligible to receive them. Teams have the option to chose from five different levels of tender offers to extend to potential restricted free agents, each of which carries a different one-year salary requirement and a different level of draft-pick compensation should that player sign with another team. All of the offers, however, give the original team the right to match any contract offer the player signs with another team.

The following 2009 Buccaneers became restricted free agents on February 27 after receiving tender offers from the team:

Penn and Ruud received tender offers that require another team to send the Buccaneers first and third-round picks in the 2010 draft in order to sign either of them away. Williams' offer returns a first-round pick while Bradley (second), Trueblood (second) and Stovall (third) all received offers that require the return of a pick equal to the round in which they were originally drafted.

Players with expiring contracts and less than three years of credit fall into a third category: exclusive rights free agents. That is what it sounds like - the player's existing team retains exclusive rights to negotiate a new contract as long as they extend the necessary tender offer at the beginning of free agency. Only two players fell into that category for the Buccaneers this year, and they became exclusive rights free agent on March 5 when the team extended the necessary tender offers.

The open market is quiet at this point, early in April, as teams begin to focus more and more on the draft. However, there is usually another rush of activity after the draft, when teams can pinpoint roster needs they were not able to address during the draft. However, that will not be true of the league's remaining restricted free agents, who have just a little more than a week left to shop their services around the NFL.