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 Sunday, Jan. 4, that “my values and approach are no longer aligned with the current direction of the organization.”

The 24-time Grand Slam champion announced at the 2020 U.S. 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 that sort of thing hasn't happened.

Djokovic said Sunday on X that he had “ongoing concerns regarding transparency, governance, and the way my voice and image have been represented.”

The PTPA filed a class-action lawsuit in March against the women’s and men’s tours, the International Tennis Federation and the sport’s integrity agency, accusing the organizations of “systemic abuse, anti-competitive practices, and a blatant disregard for player welfare.” The four Grand Slam tournaments were later added as defendants.

Djokovic was not listed as a plaintiff when the suit was filed; Pospisil and other players were.

That's because, Djokovic said in March, “I want other players to step up.”

The lawsuit says players should gain access to more earnings, arguing that the governing bodies that oversee the four Grand Slam tournaments — Wimbledon, the U.S. Open, the French Open and the Australian Open — and other professional events “cap the prize money tournaments award and limit players’ ability to earn money off the court.”

Djokovic said Sunday he "will continue to focus on my tennis, my family, and contributing to the sport in ways that reflect my principles and integrity. I wish the players and those involved the best as they move forward, but for me, this chapter is now closed.”