No man has more Australian Open titles than Djokovic, who has six in all and - until last year's shocking second-round exit - had won five of the six contested from 2011 to 2016.
Djokovic is seeded 14th and will be coming off just a couple of exhibition matches to prepare for his first-round encounter against Donald Young.
The 12-time major winner is in the same quarter as No. 4 Alexander Zverev, No. 5 Dominic Thiem and 2014 champion Stan Wawrinka, who confirmed Saturday he'd return at Melbourne Park from his own six-month layoff following surgery on his left knee.
They're all in the same half of the draw as defending champion Roger Federer, who last year returned from an extended injury time out to beat Rafael Nadal in the Australian Open final. Federer went on to win Wimbledon for his 19th major and finished the year ranked No. 2 behind Nadal, who won the French and U.S. Open titles.
That is giving Djokovic some hope.
"I mean, Roger and Rafa's year last year has shown age is just a number, especially in Roger's case," Djokovic said Saturday in his pre-tournament news conference. "I mean, he's a great example of someone that manages to take care of himself, knows how to prepare well and peak at the right time.
"He won a couple Grand Slams. Who would predict that after his six months of absence, so ... everything is possible really."
Djokovic had contested 51 consecutive Grand Slams until he missed last year's U.S. Open during his rehabilitation.
Off the court, the 30-year-old Serbian said he enjoyed a closer-to-normal family life off the court, including being there when his wife, Jelena, gave birth to their second child - a daughter Tara in September.
On the court, he used the time to work closely with coaches Agassi and Radek Stepanek to refine his service motion to improve the technique and "release the load from the elbow, obviously something that I have to do because I have the injury."
Now it's a less dramatic, more compact swing and he was happy with how it worked in an exhibition win over Thiem earlier in the week.
"It's not entirely different, but at the beginning even those small tweaks and changes have made a lot of difference mentally," he said. "I needed time to kind of get used to that change, understand whether that's good or not good for me.
Agassi had to modify his own service motion because of an injury in his career and he had input into the redesign for Djokovic.
"Both Radek and Andre have discussed a lot before the information came across to me," Djokovic said. "They spent a lot of hours analyzing my serve. I did, too."
Djokovic said his elbow wasn't 100 percent rehabilitated, but he was convinced by medical experts that he wouldn't do any further damage by playing in Australia.
Injuries to leading players have been a focus of attention in Australia. Nadal is returning from a lingering right knee problem and five-time finalist Andy Murray and Kei Nishikori have already withdrawn.
In recent months, meanwhile, ATP Finals winner Grigor Dimitrov and Zverev have moved up to No. 3 and No. 4 in the rankings, respectively, and are growing in confidence that they're on the cusp of Grand Slam breakthroughs.
Dimitrov said he's a better player than he was when he lost the semifinal here last year to Nadal, and Zverev is aiming to go deep into the second week for the first time at a major.
"I've showed on multiple occasions over the year that I can play and beat the best guys in the world," Zverev said. "Not trying to sound cocky or anything, but I've always said that I've always been working hard physically, I'm always trying to improve the performance at the Grand Slams. Hopefully I can do so," in Australia.
Nadal pulled out of the ATP Finals and skipped warmups tournaments before the Australian Open.
"Is the first time I am here without playing official match," Nadal said. "But I feel good. I really hope to be ready. I feel myself more or less playing well."
Nadal's career has regularly been disrupted by injuries, but he sees a need for a more thorough examination of the tennis schedule after the latest spate of injuries.
"There is too many injuries on the tour. I am not the one to say, but somebody has to look about what's going on," he said. "When something is happening, you need to analyze why."
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