Here's the full NFL email from this AM:
Clubs were advised of the rules for the three-day negotiating period in PP-23-15 (attached). These rules include limitations such as that a club cannot make an “offer;” or enter into a written or oral agreement of any kind, express or implied, or make promises or representations of any type concerning the terms or conditions of employment to be offered to any Unrestricted Free Agent for inclusion in a Player Contract after the start of the new League Year; or provide assurances of intent as to the future execution of an NFL Player Contract.
Clubs were further advised that “Any attempt to undermine the purpose of this negotiating period may be considered conduct detrimental to the League.” At this time, the League office is beginning investigations into a number of reported agreements with clubs. Violations will be dealt with accordingly. 2015-03-09