Serena Williams announced Tuesday that she would be sitting out the BNP Paribas Open at Indian Wells due to a knee injury, adding yet another blow to the event’s already low star power. The dominant women’s tennis star became the fourth multiple Grand Slam singles champion to pull out of the tournament.

As reported by ESPN, Serena Williams said that a lingering left knee injury, which she suffered during last year’s U.S. Open, has prevented her from training for the Indian Wells event. The report notes that of the seven multi-Grand Slam titlists, only three are scheduled to play at the BNP Paribas Open—Angelique Kerber, Svetlana Kuznetsova and Venus Williams. Other notable names that will not be at Indian Wells include Victoria Azarenka, Petra Kvitova and the still suspended Maria Sharapova, who is set to return in April.

As pointed out by ESPN, apart from Serena Williams’ injury, Victoria Azarenka recently gave birth to a two-month-old baby; Petra Kvitova is still recovering from a scary home burglary incident where she suffered stab wounds; while Maria Sharapova is still serving a 15-month drug ban. “Missing these multiple major winner, you look at the field at Indian Wells, and it demonstrates the strength of women’s tennis,” ESPN tennis broadcaster Pan Shriver said. “Hopefully, those champions all come back soon.”

Sports Illustrated notes that Serena Williams’ withdrawal, has opened up her half of the draw, which will see the likes of Elina Svitolina, CiCi Bellis, Garbine Muguruza and Belinda Bencic. World No. 3 Karolina Pliskova will move to Serena Williams’ spot in the bracket. Apart from Indian Wells, Williams also announced that she will be missing the Miami Open set for Mar. 21 to April 2.

Serena Williams’ injury opened the door for World No. 2 Angelique Kerber to reclaim the top ranking following the tournament. Williams took hold of the No. 1 spot after winning the Australian Open on January.

Related