Everything you need to know about the NFL legal tampering period, which opens today

The unofficial start of free agency began at the NFL Combine but with the official start of free agency just days away, players and agents can start negotiating with teams in what is called the legal tampering period.

What's the difference between this and the stuff that takes place at the Combine? Tampering runs rampant in Indianapolis when the entire NFL world invades one city. The NFL, knowing this is taking place, turns a blind eye to it because they know there is no way they can stop it. However, discussions that take place and the outcomes are kept mostly quiet because teams, agents and players know that it is not officially allowed.

Now, at 12 PM EST on Monday, just over 48 hours before the official start of free agency on March 9 at 4 PM EST, the NFL allows for conversation to take place with certain limitations, but not as many as in years past. Teams can discuss all aspects of the contract and this year, they can actually agree on all contract parameters. Included in those negotiating positions can be signing bonus numbers, contract length, yearly salary, and guaranteed money, to which the representative can send a response position, and the team can adjust their original position. However, a contract cannot be signed and executed until the official start of free agency. The official wording from the league, which was sent to clubs on March 2 and later obtained by Pro Football Talk, is as follows:

During the two-day negotiating period, all clubs may negotiate all aspects of an NFL Player Contract with the certified agent of any prospective UFA. However, a new club may not execute an NFL Player Contract with a prospective UFA until 4:00 p.m., New York time, on March 9, when the player's 2015 contract expires.

The only valid, binding and enforceable employment agreement between an NFL player and an NFL club is an NFL Player Contract that has been fully executed by the parties in compliance with all applicable League rules and the CBA and that any discussions regarding possible employment or terms of employment are non-binding and are unenforceable by the player or the club.

According to Ian Rapoport of the NFL Network, teams can now schedule players to come in for visits, but the agent and player must pay for their own visit. Of course, this can easily be worked around in other ways, such as a little extra more in their contract. Then again, a few hundred dollars for airfare and a hotel room is pocket change for most players.

If teams are found to have violated any rules, the memo states that it may be considered conduct detrimental to the league, as well as a violation of the league's anti-tampering policy. If an investigation is required, the league would seek all relevant documents from the team, including email and phone communications, along with a review of documents regarding travel arrangements for the player.

Last year, the deal between the Miami Dolphins and Ndamukong Suh leaked early and then more reports came out. The NFL investigated the Dolphins but found that no action was taken.

For players and agents, this period allows them to figure out their value on the open market. They can then take this information back to the team they are leaving in hopes of a deal or can put other teams against each other in order to get the most money possible.

One thing we have learned the past few years is that there is not a lot of information that leaks out during this time. Teams and agents respect the confidentiality, sensitivity and demands of the NFL. With the Suh deal leaking out last year, the NFL is sure to crack down even more in 2016.

This column was written by Matthew Cannata. Follow him on Twitter! Follow @FinsInsider