The NHLPA told ESPN.com it didn't know the league had given team GMs a 48-hour window last week to field questions from players about the lockout, which has resulted in the cancellation of all games through Nov. 1.
The union characterized the move as an end-run around the collective bargaining process.
"Most owners are not allowed to attend bargaining meetings," NHLPA counsel Steve Fehr said in a statement. "No owners are allowed to speak to the media about the bargaining.
"It is interesting that they are secretly unleashed to talk to the players about the meetings the players can attend, but the owners cannot."
NHL Deputy Commissioner Bill Daly confirmed to the website GMs were allowed to answer a limited range of questions from individual players about owners' latest collective bargaining proposal, submitted Oct. 17.
"I'm not sure why that's a big story," he said.
The league has said a deal must be reached by Thursday in order to hold a full, 82-game season that would start Nov. 2.