Serena Williams pulls out of Rogers Cup in Montreal with shoulder injury

World number one Serena Williams has withdrawn from next week's Rogers Cup in Montreal because of an injury.

The two-time champion has not played since winning her seventh Wimbledon title and has pulled out with inflammation in her shoulder.
Title holder Andy Murray, Roger Federer and Rafael Nadal have already pulled out of the men's event in Toronto.
Williams, 34, will defend her singles and doubles titles when the Olympic tennis event begins in Rio on 6 August.
"Of course, we are disappointed that Serena will not play in the tournament this year," said Toronto tournament director Eugenie Lapierre.
"Because this is an Olympic year, the players have very full schedules. Sometimes your body needs rest. We hope that Serena will recover quickly and wish her much success for the rest of the season."