Iga Swiatek has withdrawn from the Miami Open with a rib injury.
The world number was due to defend her title, having won the tournament last year without dropping a set.
However, she will be unable to feature in Florida due to an ongoing rib issue that has plagued her since the Qatar Open in February.
Swiatek reached the semi-finals of the Indian Wells Open last week, losing to eventual champion Elena Rybakina, and hinted at concerns over her condition.
The Pole confirmed on Wednesday that after consulting with her medical team, she will not play her second-round match against Claire Liu on Thursday and will also miss the Billie Jean King Cup, which takes place in April.
"You know that in and after Doha I was struggling with a strong infection," Swiatek said.
"I was allowed to play, but a strong episode of tough cough led to a rib injury. We were trying to handle it and continue to play as long as it was safe for me. We were analysing the data in the last [few] days and my doctor prepared my diagnosis.
It was a very difficult decision to make but I have no doubts that health is the most important.— Iga Świątek (@iga_swiatek) March 22, 2023
To była naprawdę bardzo trudna decyzja, ale nie mam wątpliwości, że zdrowie jest absolutnie najważniejsze. pic.twitter.com/HjBqrANmy0
"Unfortunately, I'm still feeling a lot of discomfort and pain and I can't compete.
"I will keep you updated about where I play next, because it depends on my process of recovering and the recommendation of my medical team.
"I have the best team behind me, we only need some time to deal with the injury. It's a truly difficult call to not play in Miami and the Billie Jean King Cup, but health is the most important [thing].
"I'm grateful this is the first health issue in a long time and I was able to compete in perfect shape for so long, but that's sports, it happens sometimes, without our control.
"Time to accept it and get well as soon as possible."
Swiatek will be replaced in the women's draw by lucky loser Julia Grabher.
The 21-year-old will now hope to be fully fit in time for the clay-court season, including the French Open, where she is the reigning champion.