Two-time champion Victoria Azarenka pulled out of the Sony Open tennis event on Friday, citing a right ankle injury.
The 23-year-old star was also forced to pull out of a quarterfinal at the big WTA event in Indian Wells last week because of the injury.
The former world No. 1 and reigning Australian Open champion was scheduled to meet American wild card Madison Keys in a second-round match on Day 4 at the Sony Open, but the second-seeded Belarusian was replaced in the draw by American lucky loser Lauren Davis, who outlasted Keys 6-1, 5-7, 7-6 (9-7) to advance.
Azarenka was the Miami champion in 2009 and 2011.
Sixth-seeded German Angelique Kerber came from behind to beat former French Open champion Francesca Schiavone 6-7 (5-7), 6-3, 6-2 on Friday.
Fifteenth-seeded Italian Roberta Vinci came back to beat American Christina McHale 6-7 (2-7), 6-1, 6-3, while 20th-seeded Spaniard Carla Suarez Navarro overcame American Jamie Hampton 5-7, 7-5, 7-6 (7-3), and 21st-seeded Czech Klara Zakopalova handled Spaniard Anabel Medina Garrigues 6-3, 7-6 (7-3).
Meanwhile, 2006 Miami champ Svetlana Kuznetsova took out fellow Russian Ekaterina Makarova 6-4, 6-4 and 29th-seeded Russian Elena Vesnina vaulted past Croat Donna Vekic 6-4, 6-2.