Kim Clijsters’ tennis comeback has been pushed back as she recovers from a knee injury, meaning she will miss the Australian Open.

Clijsters, 36, announced in September that she was planning to make a comeback when the new season begins in January.

Her decision to make a comeback will mark her second return to the sport after first retiring in 2007 to start a family. She last played on the WTA tour in 2012.

“I’ve had to make the decision that I will not be able to compete in January. I am undergoing rehab and treatment for a knee injury,” Clijsters said on Twitter.

“It’s a setback but I’m determined as ever to get back to the game I love.”