The world No3 pulled out of the tournament on Friday ahead of her second-round match against Madison Keys, citing the same problem that forced her withdrawal from Indian Wells earlier this month.
“The decision was really hard to make, but it was really obvious what the decision was couple days ago already,” said the 23-year-old Azarenka, who is a two-time champion in Miami.
“I wanted to give my 100 per cent possibility to play, and today was my last test. The last two days I tried to practice on it, which did not get better.
“Honestly, I have no idea [how long I will be out for] right now. In Indian Wells I heard that two to three weeks [was a] possibility.
“Obviously I don’t have that time here, so I feel like I took a step back with my recovery trying to play here and trying to push.
“It probably will go back to the two weeks maybe, maybe less. We will see how the progress. The progress was better than the doctor said, but it wasn’t enough.”