The American 23-time Grand Slam singles champion was beaten 6-1 6-0 by Briton Johanna Konta at the most recent Silicon Valley Classic event - the worst defeat of her career.

"We are disappointed Serena will not be joining us," said tournament director Eugene Lapierre.

"Fans were very much looking forward to seeing her in action."

German Tatjana Maria will now get a wildcard spot in the main draw and faces Alize Cornet of France in the first round.

"Beyond the disappointment, the tournament as a whole remains a high-level competition," Lapierre added.

"The entire top 10 is here, along with 22 of the top 25. There are exciting matches in store from the outset."