Reigning Australian Open champion Victoria Azarenka withdrew from her Fed Cup match with a lower back injury on Saturday.

She will be replaced by teammate Anastasiya Yakimova, but she is still eligible to compete on Sunday if healthy.

"It has been a while and I have been trying to take [the injury] day by day," Azarenka said in a statement. "I had the pain since the Australian Open and was hoping to recover, but did not have enough time with all the flying I did. Unfortunately, it just didn't happen. It's disappointing."