The Novak Djokovic conundrum: Work through the slump or take time off?

From an invincible machine to a vulnerable player, Novak Djokovic has been through more changes than a Shakespearean actor.

Heading into Wimbledon last year, Djokovic was the world's top-ranked player, having won four Grand Slams in a row. All the talk was of him winning the coveted calendar year Grand Slam and whether anyone could stop him. But Djokovic has struggled this year with form and shaky confidence, and is currently ranked fourth in the ATP rankings, behind Andy Murray, Rafael Nadal and Stan Wawrinka. Djokovic's only singles title came back in January at the Qatar Exxonmobil Open.

Djokovic's on-court play isn't the only aspect of his game that has changed. His coaches from last year are gone -- Boris Becker and Marian Vajda shunted aside as he looks for a new direction. Pepe Imaz, his spiritual advisor, has assumed a bigger role. Andre Agassi, who has agreed to work with him informally, will be with him at Wimbledon, but nothing is set beyond that. In another sign his game is out of sync, Djokovic is playing in an ATP event this week in Eastbourne, England -- the first time in 11 years he has competed the week before Wimbledon.

Although Djokovic believes he has played better the past two months, he readily admits he must be more consistent. "Twelve months ago, I had four Grand Slams under my belt and I went into Wimbledon completely different mentally compared with how I am today," he told reporters in Eastbourne. "I still have to trust myself, my abilities to play well, and to win against anybody on any surface."

It seems unlikely Djokovic will snap out of his funk to win a fourth singles title at Wimbledon. The next phase of his career could depend on what he chooses to do the next few months. With a second child due with wife Jelena this summer, he may spend more time with his family. When he lost in the French Open quarterfinals earlier this month, he hinted he might consider taking time off.

Former world No. 1 Mats Wilander, a TV analyst for Eurosport at Wimbledon, struggled with motivation after he won three of the four Grand Slams in 1988, never winning another. The Swede said a break, perhaps even skipping the US Open, could be best for Djokovic.

"With a new baby on its way, I would think he would take some time off after Wimbledon, drop out of the hard-court season and get all sorted," Wilander said. "[Then] train like crazy, just like Nadal and Federer for four or five months, dare to take time off and also allow himself to improve his game and get better at certain things."

If Djokovic takes times off until the Australian Open in January, he could come back stronger mentally and physically, Wilander said. A break would also give him a chance to work on improving his backhand, which is similar in form to Agassi's two-hander.

If anyone knows what Djokovic might be going through, it's Bob and Mike Bryan, the American twins who have won 16 Grand Slams together. After they won their landmark 10th doubles title, they struggled to keep their game at a high level.

"You've got to recalibrate your goals," Mike Bryan said. "Once you win the career Slam, or you win four Slams in a row, sometimes you just exhale, and you just take the foot off the gas. I think he's hungry again, he wants to do it and it [can] just take one Slam to get reinvigorated and excited about it again."

Added Bob Bryan: "There's only so much a human mind can push. He's just going to find a new chapter in his career right now, and I have no doubt he's going to back on the top."

Milos Raonic, who came through the draw vacated by Djokovic at Wimbledon last year to reach the final, said he also expects the Serb to be back on top before long.

"I think it's a question of [winning] one or two important matches," he said last week. "That's going to make the difference for him. All those can happen in one tournament or they can happen over a spread period of time."