Former world number one Serena Williams has withdrawn from next week’s WTA tournament in Montreal citing “personal reasons,” organizers said Saturday.

“Of course, we are disappointed that Serena will not be joining us,” tournament director Eugene Lapierre said in a statement, noting that despite the 23-time Grand Slam winner’s absence, all of the top 10 players in the world are in the draw for one of the key tuneups for the US Open.

With Williams’ withdrawal, Germany’s Tatjana Maria gains direct entry into the draw. She’ll face France’s Alize Cornet in the first round.

The winner of that match could face fourth-seeded Wimbledon champion Angelique Kerber in the second round.

Williams, 36, battled back from life-saving surgery after giving birth to daughter Olympia in September, reaching the final at Wimbledon, where she was beaten by Germany’s Kerber in straight sets.

On Tuesday, Williams endured the most lopsided defeat of her WTA career when she fell 6-1, 6-0 to Briton Johanna Konta in San Jose, California.

“I have so many things on my mind that I don’t have time to be shocked about a loss where I clearly wasn’t at my best,” Williams said after that defeat.