Two-time Wimbledon champion Petra Kvitova has withdrawn from the Rogers Cup due to injury, Tennis Canada announced on Friday.
Kvitova was hoping for a repeat of her 2012 performance in which she won the Rogers Cup, but is nursing an arm issue that flared up during the French Open earlier this year.
As a result of Kvitova not being able to compete, three-time Rogers Cup champion Serena Williams becomes a top-eight seed and will play her opening match on Wednesday night.
Williams won the tournament in 2001, 2011 and 2013.
Venus Williams will take the available spot in the main draw, with her WTA Wild Card spot being given to two-time Grand Slam champion Svetlana Kuznetsova.
The Rogers Cup kicks off on August 3.