The Czech should have played the quarterfinals against the Frenchwoman Varvara Gracheva on Thursday, but announced her withdrawal just hours before the match started.
The injury occurred during her victory over the Briton Jodie Burrage in the second round and worsened overnight.
It did not get better, rather worse. With Wimbledon around the corner, it seems wisest to rest and investigate what is going on, says Krejcikova according to AFP.
The 29-year-old is waiting for the X-ray results before deciding whether she can participate in Wimbledon, which begins in just a few days.
Krejcikova has had a tough year. She missed the Australian Open due to a back injury and was eliminated early from the French Championships. In Eastbourne, she saved several match balls in both her victories before she was forced to throw in the towel.
