Twelve-times grand slam champion Novak Djokovic will miss the rest of the tennis season, including next month’s U.S. Open, to recover from a right elbow injury, the Serbian said on Wednesday.

The 30-year-old posted a video statement on Facebook in which he said he had decided to let heal the injury which caused him to retire during his Wimbledon quarter-final against Czech Tomas Berdych earlier this month.

“I’ve made a decision to not play any competitions or tournaments for the rest of the 2017 season,” Djokovic, down at number four in the world rankings for the first time since 2009, said. “It’s a decision that had to be made.”

Djokovic then told a news conference he had decided to take six months off after consulting doctors and specialists in Serbia and abroad.

“I have been dragging this injury for the past 18 months and it has escalated in the last month or two,” Djokovic, who will miss a grand slam for the first time since 2004 at Flushing Meadows, said. “It became very painful at Wimbledon, where unfortunately I had to retire against Berdych.”

He said surgery would not be necessary, however.