PARIS, June 3 (Reuters) - Rafael Nadal's season is all but over after he underwent surgery on a hip muscle which will keep him out of action for an estimated five months, his representative said on Saturday.

The 14-times French Open champion, who has won a men's joint-record 22 majors, has been out of action since January after hurting his hip flexor in his second-round match at the Australian Open.

"Rafa will begin his progressive functional rehabilitation in a few hours and the normal recovery process is estimated at five months, always taking into account respecting the biological times of said structure," Benito Perez-Barbadillo said.

The 37-year-old Spaniard has said 2024 is likely to be his last year as a professional player.

He was initially set to miss up to eight weeks but skipped claycourt tournaments in Madrid and Rome to build his fitness after being ruled out of events at Indian Wells, Miami, Monte Carlo and Barcelona this season.

In March, Nadal fell out of the top 10 in the world rankings for the first time since 2005 and is now 15th.

(Reporting by Julien Pretot; Editing by Ed Osmond)