India, Jan. 6 -- Novak Djokovic is cutting ties with the Professional Tennis Players Association, a group he co-founded that sued the sport's governing bodies last year, writing on social media that "my values and approach are no longer aligned with the current direction of the organisation."

The 24-time Grand Slam champion announced at the 2020 US Open that he and now-retired Canadian player Vasek Pospisil were launching the PTPA. They said they were aiming to offer representation for players who are independent contractors in a largely individual sport.

One of the goals made clear along the way was to become a sort of full-fledged union that negotiates collective bargaining agreements like those that exist in team sports, although tha...