Emma Raducanu's Wimbledon preparations were thrown into turmoil after the US Open champion was forced to retire from her Nottingham Open first round match on Tuesday.
Raducanu needed a medical timeout in the early stages of her clash with Switzerland's Viktorija Golubic after suffering an injury.
The 19-year-old Briton received treatment on her left side and took painkillers in an attempt to carry on, but had to pull out after just 33 minutes while trailing 4-3 in the first set.
It was the third time Raducanu had withdrawn from a tournament due to injury since she burst onto the tennis scene with her stunning US Open triumph in September last year.
The world number 11 also bowed out of matches in Guadalajara in February and Rome in May with injuries.
Raducanu is due to play in Birmingham next week, but she has "no idea" if she will be ready for Wimbledon, with the grass-court Grand Slam starting on June 27.
"I think I pulled something. I'm not really sure what exactly happened. An absolute freak injury. I don't know what I could have done about it," Raducanu said.
"I need to get a scan first. I am not going to 'Google doctor' myself. I will get it checked out. Then we will see from there.
"I have no idea (about Wimbledon). It could have just seized up and gone into spasm and then it is really bad for a few days. I cannot diagnose myself. I will get it checked out."
The latest retirement will raise further questions about Raducanu's fitness as she continues to struggle with the physical demands of life on the WTA Tour.
Raducanu, who made her WTA debut at Nottingham 12 months ago, has not won more than two matches at a tournament since her remarkable journey from the qualifying rounds to the title at the US Open.
In her first match on British soil since that astonishing victory at Flushing Meadows, the signs of discomfort were there early on as Raducanu was seen holding her side in the opening game of the match.
Her first round of treatment came at the first change of ends and although she was able to open a 3-1 lead, it was clear she was in pain and called time having lost three games in a row.