World number 31 Andreescu retired from her fourth-round match against Russia's Ekaterina Alexandrova in Miami on Monday and left the court in a wheelchair after screaming in pain having fallen while moving across the baseline.
The Canadian, who reached a career-high fourth in the rankings in 2019 but has suffered with a number of injuries, said the rehabilitation process has already begun.
"It's tough to say exactly how long it will take, but let's just say it could've been much worse !!" Andreescu wrote on Twitter.
"I'm going to take it day by day, and I am optimistic that with the right work, rehab, and preparation, I'll be back on court soon."
Andreescu, who retired with a shoulder injury during her semi-final match at the Thailand Open in February, is still looking for her first title since the 2019 US Open.
