Emma Raducanu has withdrawn from the Miami Open with a lower back injury. The 2021 US Open champion had been scheduled to face Wang Xiyu in the first round on the opening day of play Tuesday.

"I have been experiencing lower back pain and at this stage of my return to competition I don’t want to risk anything happening," Raducanu said in a statement from the tournament. "I really tried my best to be ready and I’m sad to be pulling out of Miami as it’s a cool tournament but wish the event all the best."

Raducanu returned to action in January following an eight-month layoff in 2023 because of multiple wrist and ankle surgeries. She has compiled a 5-5 record across five tournaments, including a third-round run in Indian Wells last week.

The Briton was the second player to withdraw from Miami after the start of the qualifying event, following Viktorija Golubic, who pulled out with a left foot injury. As such, they have been replaced by two lucky losers -- Tamara Korpatsch, who has drawn Viktoriya Tomova in the first round, and Bernarda Pera, who will take on Danielle Collins.

18th seed Barbora Krejcikova also withdrew on Day 1 due to illness. The Czech was replaced by lucky loser Greet Minnen, who will face either Lesia Tsurenko or Magda Linette in the second round. 

Wang will now face qualifier Anna Karolina Schmiedlova. Other qualifiers include Laura Siegemund and Aleksandra Krunic, who will meet in the first round with the winner to face No.9 seed Jelena Ostapenko. Clara Tauson also qualified, and will face Caroline Dolehide with the winner to take on last year's runner-up, No.4 seed Elena Rybakina.

Former Roland Garros semifinalist Nadia Podoroska came through as well, and will face Ashlyn Krueger with the winner to play No.3 seed Coco Gauff.