Japan's Kei Nishikori will be sidelined for up to six months after undergoing surgery for a hip injury, the former world number four said on Tuesday.

The injury forced the 32-year-old to withdraw from this month's Australian Open Grand Slam.

He last played at the ATP Masters 1000 event in Indian Wells, before ending his 2021 season in November due to a separate back injury.

READ: Australian Open 2022: Nadal focused on enjoying his tennis, not Grand Slam record

"After trying several different rehab options I have decided, together with my medical team, to have arthroscopic hip surgery this week," Nishikori said in a post on his app.

"I will work as hard as I can, and the goal is to be back in about six months."

Nishikori, who reached a career-high ranking of fourth shortly after becoming the first man from Asia to reach a major final at the 2014 US Open, has been plagued by injuries in recent years and has struggled for consistency.