An earthquake shook the sporting universe this week: Serena Williams, the 23-time Grand Slam tennis champion, has taken the first step toward a potential comeback by reentering the sport’s anti-doping test pool. After news reports surfaced on Tuesday of her registration with the International Tennis Integrity Agency, Williams tried to quell speculation about a potential return to play for the first time since 2022. “Omg yall I’m NOT coming back,” she posted on X.

Whether or not she ever plays another professional point, Williams is now the highest-profile athlete known to be taking a GLP-1 drug who has submitted herself to the testing pool. Her participation comes at a time when the sports world is actively evaluating whether drugs like Ozempic, Wegovy and Mounjaro should be allowed in elite competition.