NFL Players Association executive director DeMaurice Smith has announced that the union are to launch an "investigation" into events that lead to the release of medical information about Tampa Bay Buccaneers quarterback Josh Freeman.
A unknown source leaked information to the media that Freeman was in stage one of the NFL's substance-abuse programme and suffered from ADHD, claims that the quarterback has denied.
Smith told reporters: "We are sufficiently concerned about what we've heard to begin an investigation. We have a collective bargaining agreement that mandates and protects confidentiality and privacy.
"If we believe that any member of the team management or anyone from the league has deliberately taken steps to thwart that privacy and to breach that confidentiality, this union will take every step and file every grievance and pursue any law to rectify that. We believe that it's important to maintain the confidentiality."
The NFL owners and players recently agreed on a new contract bargaining agreement before the 2011 season after a lengthy dispute, which governs the rules and regulations of the game involving the players.