Kvitova injury boosts Williams sisters in Canada
Petra Kvitova has dropped out of next week's Rogers Cup in Toronto, resulting in Serena Williams being upgraded to a top-eight seed.
The two-time Wimbledon champion has not recovered from an arm injury which has dogged her season, according to tournament officials.
Former world number one Williams now receives a top-eight seeding for the event which starts on Saturday, with Simona Halep the defending champion.
Her older sister Venus will take the available space in the main draw, while a wildcard spot will go to Svetlana Kuznetsova.
Kvitova said in a statement she had pulled out after the left arm injury that forced her to withdraw from the French Open flared up again.
"I'm so disappointed to have to withdraw from the Rogers Cup," said Kvitova, who pulled out of the French Open but played at Wimbledon last month.
"My forearm injury is continuing to cause some problems, so on the advice of my medical team, I have made the decision not to travel to Canada."
Simon Barlow has a wealth of journalism experience and in-depth knowledge in a number of sports. As well as his extensive football knowledge, Simon is also well versed on cricket, tennis, American Football and cycling amongst others.