Nishikori and Stephens out of Brisbane International

Kei Nishikori withdrew on Saturday from the season-opening Brisbane International to continue his recovery from a wrist injury. Nishikori, 27, has been out of action for more than four months and has dropped out of the top 10.

Kei Nishikori said he had hoped to play in Brisbane as part of preparations for the season's first Grand Slam event at the Australian Open in Melbourne. Arnd Wiegmann/Reuters

"I am so disappointed to miss Brisbane this year," said the world number 22 on the tournament's official Twitter account. "For years, it's been my first tournament of the season and I always feel so at home."

Nishikori said last month he had chosen rehabilitation over surgery to repair the damage and was targeting a return to action at the Brisbane International to prepare for the Australian Open.

US Open champion Sloane Stephens has also been ruled out of the Brisbane women's tournament with a knee injury. "Sloane Stephens needs an extra week's rehab on her knee, meaning she will now not play the Brisbane International," the organisers tweeted.

The Brisbane International takes place from 31 December to 7 January. The men’s field will be led by world number one Rafael Nadal. Grigor Dimitrov, who won the ATP Tour Finals in London in November, is also scheduled to play. Nick Kyrgios will carry the hopes for the locals.

The world number 21 has vowed to knuckle down as part of his attempt to climb the rankings. “Playing lots of basketball wasn’t great for my body," said the 22-year-old Australian. "People have told me that and now I’m starting to listen. So I’m feeling fit and healthy and as motivated as I have for a while.”