Nadal. who is sitting out the current U.S. Open and missed the Olympics tennis tournament last month, said he will also be sidelined for Spain's Davis Cup semifinal next week.
"I have to recover and I'll be back once the pain is gone," Nadal said.
The 11-time Grand Slam winner's last match came in the second round at Wimbledon in June, when he fell to the Czech Republic's Lukas Rosol.
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