China's Wang will advance to the last 16 via a walkover and face Madison Keys.
"Unfortunately I tried my best to recover, but the injury I sustained in Toronto and also pushed by the second round match, I didn’t recover as I wish I could to get ready for my next round," Svitolina said in a statement.
"Have of course great memories of playing here and going deep in the tournament. Had a great match here two nights ago. Very sad to pull out this round."
The Ukrainian took a medical timeout to address her right foot during the second set of her second-round match against Tereza Valentova on Sunday but continued to win 3-6, 7-6(5), 6-0.
Svitolina is next scheduled to play at the US Open, which begins later this month.