Last week, a historic NBA strike dominated the headlines. The Milwaukee Bucks’ decision to sit a game out spread across the league and then to the Women’s NBA, Major League Soccer, and even, remarkably, Major League Baseball and the National Hockey League. The Bucks took action in response to the shooting of Jacob Blake by police in Kenosha, Wisconsin, and the ongoing murder and brutalization of black people by the police in the United States.

While NBA players have since returned to work — after contentious negotiations, and with a nudge from Barack Obama — there is another labor story in the world of professional sports: some of tennis’s top male stars are pushing to form a players’ association, separate from the existing structure of the Association of Tennis Professionals (ATP), which jointly represents players and tournaments. But there are serious questions as to how much support the new association has, and what its purpose would be.

As reported by the Associated Press, “No. 1-ranked Novak Djokovic and former top-30 member Vasek Pospisil would be the co-presidents of a new group they are trying to set up to represent men’s professional tennis players.” A letter obtained by AP on Friday, sent to players before the start of this week’s US Open, seeks the creation of a Professional Tennis Players Association (PTPA).