Four-time grand slam winner Maria Sharapova on Monday withdrew from next week’s Stanford WTA hardcourt event due to a hip injury that has bothered her since Wimbledon.

The world number two told organisers that she would not be able to play at the tournament won by Serena Williams the last two years. The pullout came shortly after the LA-based Russian announced former men’s great Jimmy Connors is her new coach.

With the additional withdrawal of Wimbledon semi-finalist Kirsten Flipkens of Belgium, the two open places in the draw go to Slovak Daniela Hantuchova and American Christina McHale.

“We are disappointed for our fans that Maria (Sharapova) won’t be able to attend this year, but unfortunately injuries are a part of the sport and we understand that a player’s health must always come first,” said tournament boss Kim Hall.

“We wish her a speedy recovery and hope she is able to return to the court soon.” Other entries at the first event in the North American run-up to the US Open next month include Wimbledon champion Marion Bartoli, current number four Agnieszka Radwanska, 2011 US Open champion Samantha Stosur and 2010 French Open winner Francesca Schiavone.