Tonsillitis has forced Emma Raducanu to withdraw from this week's WTA event in Austin, Texas.
The number one player in Great Britain has only participated in four matches this year after twisting her ankle in Auckland in January.
The 20-year-old was scheduled to play her first match since losing to Coco Gauff in the second round of the Australian Open in the new tournament in Texas, but she withdrew before the draw overnight.
"I'm sorry to have to withdraw from the ATX Open. I am currently suffering from tonsillitis and am unable to compete this week. Thank you to the tournament and the great hospitality here in Austin," said Raducanu.
The Briton will stay in Austin and then travel to Indian Wells, California, before the Miami Open, according to Raducanu's management.
The 20-year-old, who won the 2021 US Open, dropped to 80th in the WTA rankings and missed the cut for Indian Wells' women's main draw, but she was given a wild card entrance into the WTA 1000 competition.
Sebastien Sachs is Raducanu's fifth coach with whom she is presently working.
Sachs, who has previously coached with Germany's Julia Gorges and former world number one Victoria Azarenka, helped Belinda Bencic win the Olympic gold in Tokyo 2020.
ATX Open is scheduled to take place from February 27 to March 5. A 16-team doubles field will also be present at the event, which will be the first WTA tournament to be staged in the United States during its 50th anniversary year.