Emma Raducanu has "no idea" if she will be fit for Wimbledon after retiring from her first-round match against Viktorija Golubic at the Nottingham Open on Tuesday.
Second seed Raducanu conceded the match after 36 minutes having sustained an injury to her left side while down a break at 4-3 in the opening set.
The 19-year-old is scheduled to appear at Birmingham next week before heading to Wimbledon, where she reached the fourth round last year.
US Open champion Raducanu, who made her WTA Tour debut in Nottingham last year, is unsure if she will recover in time to feature at the All England Club.
"I think I pulled something, I am not really sure what exactly happened," Raducanu said.
"I have just come off court, an absolute freak injury. I don't know what I could have done more about it. That is it.
"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 have no idea. I cannot diagnose myself. I will get it checked out."
Raducanu was the only seed to exit the tournament, with top seed Maria Sakkari overcoming Camila Osorio 6-2 6-3 to advance to a second-round meeting with Rebecca Marino.
Beatriz Haddad Maia came from a set down to beat Wang Qiang 5-7 6-4 6-3, while Ajla Tomljanovic and Camila Giorgi had comfortable victories against Wang Xinyu and Sonay Kartal respectively.
Aryna Sabalenka cruised into the second round of the Rosmalen Grass Court Championships by defeating Kateryna Baindl 6-4 6-1.
Fifth seed Liudmila Samsonova, meanwhile, succumbed to a 6-3 6-4 loss to Ann Li in an hour and 22 minutes.
There would have been further casualties among the seeds had Tamara Zidansek, Ekaterina Alexandrova and Elise Mertens not fought from a set down to win their opening matches.