BRISBANE, Australia (AP) -- Juan Martin del Potro of Argentina has withdrawn from the Brisbane International with a left wrist injury, joining another former U.S. Open champion, Marin Cilic, on the tournament sidelines.

Del Potro has been off the tour since undergoing surgery in March, but had targeted Brisbane as his return. The withdrawal of the 2009 U.S. Open champion also leaves him in doubt for the Australian Open, while he appears unlikely to defend the Sydney International he won last year.

Cilic, who has a right shoulder injury, announced his withdrawal Tuesday.

Roger Federer, Milos Raonic, Kei Nishikori and defending Lleyton Hewitt are playing in the men's event at Brisbane, while Victoria Azarenka and Sam Stosur are among those in the women's draw.