The German also took part in the protests at Roland Garros Media Day and confessed to feeling recovered from his back issues.
The world number one joins the protests and only gives a 15-minute press conference: "We are trying to put ourselves in a position where we can have some voice."
The Pole joined the protest to limit press conferences to a maximum of 15 minutes and is now not ruling out a future boycott: "It's difficult to know what will happen in the coming weeks."
The Serb lands at Roland Garros with the dream of his 25th Grand Slam and also with that of a united tennis: "We must find a common voice to build a better structure and a better future for tennis."
