Tommy Haas needs a fourth operation on his right shoulder and will miss the rest of the tennis season.
The 20th-ranked German retired from his opening match at the French Open last month and withdrew from last week's Gerry Weber Open in Halle to assess the injury.
The 36-year-old player's management company said Monday that Haas has three damaged tendons in his right shoulder, which was operated on in 2002, 2003 and 2007.
Haas says ''the diagnosis was a real shock'' and surgery ''can't be avoided because the injury is very serious.''
Haas, once ranked No. 2 in the world, will undergo surgery Tuesday in New York.
He says he no plans to retire and hopes for a comeback in 2015.
''I'm still totally convinced I've good matches and tournaments ahead of me," Haas said.
