This is a new step for the NFL, but they've now figured out a way to dominate midnight on a Friday in March.
As of midnight EST/11 p.m. CST on Saturday, March 9th, teams and agents can begin contract negotiations. No deal can become official until 4 p.m. EDT/3 p.m. CDT on Tuesday, March 12th but, until then, there will be wheeling, dealing, and offering between all teams and any player with an agent. Players without an agent's representation, such as safety Ed Reed or outside linebacker Paul Kruger, cannot negotiate with any team other than their 2012 employer.
No pursuing team can have contact with a player nor can a player visit any team facility, save their most recent employer, until free agency officially begins on Tuesday afternoon. Thus, your Houston Texans can bring in outside linebacker Connor Barwin and safety Glover Quin, but their agents will also be hearing from other teams to see how full the market is for their services.
Consider this an open thread for tonight's activities as news, rumors, and misinformation begin to hit the Interwebs. Will Houston's gamble to let their free agents test the market pay off? We'll soon find out.