Carlos Alcaraz was taken aback by the news of a class-action lawsuit filed in US federal court against some tennis governing bodies. He clarified on Wednesday that he does not support the effort initiated by the players' association co-founded by Novak Djokovic.

"There are some things that I agree (with). There are some other things that I (don't) agree with," Alcaraz commented about the antitrust case during a pre-tournament press conference for the Miami Open, where he is the second seed. "But the main thing here is that I am not supporting that. So that's it."

The Professional Tennis Players' Association, claiming to have the backing of over 250 athletes, launched a lawsuit in New York on Tuesday. It also took action in Brussels and London, labelling the organisations running the sport - the women's (WTA) and men's (ATP) tours, the International Tennis Federation (ITF), and the agency overseeing anti-doping and anti-corruption efforts (ITIA) - as a "cartel".

"Honestly, it was surprising for me, because nobody told me (anything) about it," Alcaraz admitted. "So I just saw it on social media."

The 21-year-old Spaniard was also surprised to find his name quoted in the over 150-page filing, like several other players.

On page 71, discussing the gruelling schedule in professional tennis, the book highlights comments from major champions Alcaraz, Coco Gauff, and Iga Swiatek. It includes a quote from Carlos Alcaraz who lambasted the Tours' calendar, stating that the Governing Body Defendants "Carlos Alcaraz criticized the Tours' schedule, saying the Governing Body Defendants 'are going to kill (players) in some way.'".

This remark traces back to Alcaraz's words at a Laver Cup event last September, as per a news conference transcript.

Alcaraz shared his thoughts on the matter: "A lot of players (want) to play more - or even more. A lot of players feel like, OK, it is a good calendar. And a lot of players (say) that it's really tight and a lot of tournaments during the whole year," he commented. "I'm the kind of player who (thinks) there is a lot of tournaments during the year, mandatory tournaments, and probably during the next few years, gonna be even more tournaments, more mandatory tournaments. So, I mean, probably they are going to kill us in some way."

The transcript noted that he was smiling as he concluded his statement.

The PTPA lawsuit hurls several accusations at tennis's governing bodies, including capping tournament prize money, stifling competition from alternative tours or events, implementing a restrictive rankings system that dictates athlete participation, and employing a "heavy-handed approach" by the International Tennis Integrity Agency, which the suit describes as "arbitrary and selective."