Serbian tennis player Novak Djokovic speaks during a press conference in Belgrade on July 26, 2017. Twelve-time Grand Slam champion Novak Djokovic will miss the rest of the season with an elbow injury, he announced on July 26. [Photo/VCG]

Djokovic will miss the US Open, ending his streak of participating in 51 consecutive Grand Slam tournaments, and aims to return to the ATP tour in January. He made the announcement Wednesday — exactly a year to the day after Roger Federer said he would be sidelined for the second half of last season.

"This is one of those injuries where nothing can really help instantly. You just have to allow natural rehabilitation to take its course," Djokovic said. "Professionally, this is not, obviously, an easy decision for me."Since entering his first major tournament at the 2005 Australian Open, Djokovic has never missed one, the third-longest active run among men and seventh-longest in history.

In that time, the 30-year-old Serb has won 12 Grand Slam titles, including the US Open in 2011 and 2015. Only three men have won more major tennis singles championships: Federer (19), Rafael Nadal (15) and Pete Sampras (14).

"The remarkable series has come to an end," Djokovic said. "My body has its limits, and I have to respect that and be grateful for all that I have achieved so far."He said that Andre Agassi, with whom he recently began working on a part-time basis, will be his coach after the hiatus. Djokovic plans to start with a tuneup tournament ahead of the Australian Open at the start of 2018.

Serbia's Novak Djokovic in action during his quarter final match against Czech Republic's Tomas Berdych in London, Britain, on July 12, 2017. [Photo/Agencies]

"He supports my decision to take a break and remains my head coach," Djokovic said about Agassi, also noting that he'll be looking for a new fitness trainer. "He is going to help me get back into shape and bounce back strong after the recovery period." Djokovic made his announcement via Facebook , his website and at a news conference in Belgrade, Serbia.

His last match was on July 12, when he stopped playing during his Wimbledon quarterfinal against Tomas Berdych because the elbow was too painful. Djokovic said then he had been struggling with the elbow on his racket-swinging arm for about 1 years, which he reiterated Wednesday. He said he does not need surgery.

Since winning the 2016 French Open to become the eighth man to complete a career Grand Slam and the first man in nearly a half-century to win four consecutive major trophies, Djokovic's form has dipped. His ranking dropped from No 1 to No 4; he failed to defend any of those major titles.

He acknowledged Wednesday that he "felt worn out" and "flat" after the run of success that culminated at Roland Garros in 2016.

"I was searching for myself, for motivation," he said.

Djokovic made it past the quarterfinals at only one of the past five majors: last year's US Open, where he lost in the final to Stan Wawrinka.

Djokovic, who also mentioned Wednesday that his wife is expecting their second child, reached at least the semifinals at Arthur Ashe Stadium each of the past 10 years. That includes seven appearances in the final.

Henri Laaksonen of Switzerland, who is ranked 95th, will get Djokovic's spot in the field at Flushing Meadows. This year's US Open starts Aug 28.

"All the doctors I've consulted, and all the specialists I have visited, in Serbia and all over the world, have agreed that this injury requires rest. A prolonged break from the sport is inevitable," Djokovic said. "I'll do whatever it takes to recover."Federer demonstrated the benefits of a break last year, sitting out after Wimbledon to let his surgically repaired left knee heal fully.

He missed the Rio Olympics and US Open and dropped out of the top 10 in the rankings.

But Federer was rejuvenated at age 35 when he returned at the beginning of this season and won the Australian Open to end a 4?-year Grand Slam drought, plus titles at Indian Wells and Miami. He took more time off after that, missing the clay-court circuit, and returned for the grass, winning his eighth Wimbledon championship and 19th major title overall this month.

"Well, I hope it's not a trend," Federer said about lengthy absences, the day after he won Wimbledon. "You've got to have the same issues that I had. I didn't just walk away from the game for six months last year just because I was in the mood to. I actually had to, so it's a big difference there, as well. But, yes, everybody needs to manage their own schedules."

AP