In the past, working out midnight deals with free agents prior to the start of free agency was a bit of a gray area and technically considered "tampering" but everyone in the league did it. Going forward however, teams can now begin negotiating with free agents at midnight during what's been tabbed as the "legal tampering" period.
From midnight Friday evening until Tuesday, March 12 at 4 p.m. teams can negotiate with free agents without facing tampering charges and can agree in principal to deals, but deals cannot be submitted to the league office and approved until the official start of free agency at 4 p.m. on March 12.
Players cannot actually meet with teams during this period, but teams may discuss deals with agents and line up visits for players who want to actually visit the facility and such before signing.
Deals worked out over the next three days will likely be more so teams re-signing their own players as agents can get a good feel for what kind of market there will be with their players. I don't expect the Jaguars to be all that active in regards to putting feelers out for the high dollar free agents over the weekend, but later in the week after free agency has started they could jump into the action.