The fight between NBA players union executive director Billy Hunter and president Derek Fisher is escalating, with Hunter hiring a public relations firm and calling for a player representative conference call as early as Friday in an attempt to oust Fisher, sources said Friday morning.

The two union leaders have been at odds since a rumor surfaced during the lockout that Fisher had met privately with commissioner David Stern and deputy commissioner Adam Silver to cut a deal, a rumor that never was substantiated and that some in Fisher’s circle now suspect came from Hunter to undermine Fisher’s authority, sources said.

The board’s attempt to oust Fisher was first reported by Yahoo! Sports.

Fisher sent a letter earlier this week to player reps informing them the union’s executive committee had decided that the players union should undergo a business review, according to one Eastern Conference player representative. Several executive committee members, however, were surprised by the tone of the letter because the decision was not unanimous, another source said.

– Reported by Ric Bucher of ESPN the Magazine