Victoria Azarenka has pulled out of the Fed Cup tie against the United States with a lower back injury. Azarenka stated:
It has been a while and I have been trying to take [the injury] day by day. 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.
A lower back injury is very hard to prove even from a medical stand point, thus Im not too sure if its an injury or just a bit of a niggle which means she can have another week to relax a bit after her Australian Open win.