(Reuters) - Japan's Kei Nishikori will miss the rest of the 2017 season after tearing a tendon in his right wrist, his manager said on Wednesday.
The 27-year-old world number nine becomes the latest of a clutch of high-ranked players to take time out from the sport due to injury.
Fourth-ranked Stan Wawrinka and number five Novak Djokovic have in recent weeks called a halt to their seasons to recover from knee and elbow injuries respectively.
Nishikori was scheduled to play at this week's Cincinnati Masters, a warm-up event for the U.S. Open, but withdrew when he felt a sharp pain in his wrist during practise on Sunday.
"Kei hit a serve and heard a 'pop' in his wrist," his manager said in a statement. "It has become clear that Kei has a tear in one of the tendons in the right wrist.
"At this stage, we have elected not to do surgery and Kei is in a cast. After the swelling comes down in the next weeks, we will evaluate next steps. Kei will withdraw from all the 2017 tournaments and work hard to be ready for next year."
The Japanese reached his only grand slam final at the U.S. Open in 2014, losing to Croatia's Marin Cilic.
Injury worries have also forced four other top-ten players - Cilic (adductor), Roger Federer (back), Andy Murray (hip) and Milos Raonic (wrist) - to miss Cincinnati.