Australian Open organizers said Saturday that U.S. Open champion Bianca Andreescu, Juan Martin del Potro and Richard Gasquet have withdrawn due to knee injuries.

“The Australian Open is unfortunately too soon in my rehab process and I sadly will not be able to play in it this year," Andreescu said. “It was a very tough decision to make as I love to play in Melbourne but I have to respect the recuperation plan for my (left) knee and body."

The Australian Open, the first Grand Slam of the season, starts Jan. 20 in Melbourne. Tournament officials said on Twitter that Gasquet had withdrawn with a knee injury while del Potro was also recovering from a knee ailment.

The 19-year-old Andreescu, Canada's first winner of a Grand Slam singles tournament, hasn't played since suffering the injury at the WTA Finals in October in China.

A shoulder injury last March kept her out of all but one match from April through July.

She retired after one match at last year's French Open, didn't play at Wimbledon in 2019, before going on to win the U.S. Open.