Former world No.1 Kim Clijsters has withdrawn from a US Open warm-up event in New York due to an abdominal injury but remains hopeful of playing in the grand slam later this month.

The Western & Southern Open serves as preparation for players ahead of the August 31-September 13 US Open where Clijsters, 37, received a wildcard entry.

“It’s disappointing to have to withdraw but after discussions with medical and my team, I need a little more recovery time,” Clijsters, who won the event in 2010, said in a statement on Friday.

“I’m grateful to be able to stay in the ‘bubble’ and continue to prepare with my team here at the USTA Billie Jean King National Tennis Center.”

Clijsters, who made a return to tennis this year after nearly eight years away, won the US Open in 2005, 2009 and 2010.

The four-times Grand Slam champion’s planned comeback in January was pushed back to February because of a knee injury and she played in Dubai and Monterrey before the tour was suspended due to COVID-19.