Can Roger, Rafa slow the sublime Serb?

Who would have thought one year ago the great Roger Federer-Rafael Nadal rivalry would take a backseat to anyone? But here we are, embarking on a 2012 season that starts with one name: Novak Djokovic. His historic season took center stage over the dynamic duo that has collectively compiled 26 Slams.

Can Federer or Nadal reclaim his throne and dampen the Djokovic dominance? We look at whether either can upend the defending Aussie champ.

Roger Federer

How will the back injury affect him?

Federer has never retired from a match and doesn't like giving out walkovers, either, so it was worrying when he withdrew prior to his semifinal against Jo-Wilfried Tsonga in Doha. His only other walkover also had ties to France, occurring at the Paris Masters in 2008.

Yes, it was a back injury and Federer also said at the time his withdrawal was a precaution. Just over a week later, he took part at the elite Masters Cup -- and lost two of his three encounters, admittedly against stiffer competition than he'll face early in Melbourne.

Further, a tender back, Federer said, hampered him at Wimbledon in 2010 (when he lost to Tomas Berdych in the quarterfinals).

Federer has competed at the Australian Open with less than 100 percent strength, too. Unknown to him then, he had a mild case of mono in 2008. Djokovic beat him in the semis that year.

Federer has won majors nursing minor injuries in the past. But he wasn't 30 years old, either.

What are his chances against Djokovic?

Federer must be fully fit against Djokovic to have a chance of winning if they meet -- or hope that Djokovic is also ailing.

That's a start.

Federer clearly has the game to put Djokovic on the defensive and hit through the world No. 1, something Nadal can't do nearly as well. When Federer had success against Djokovic, he more often than not served well. (Unfortunately for him, when he's had back issues, the serve becomes less potent and he can throw in double faults.)

The Swiss was a point away from going 2-1 against Djokovic at the Slams in 2011.

What's the bottom line?

No matter what the degree, injuries and illness aren't a good sign immediately ahead of majors. We know that. Take Nadal last year: Chasing the "Rafa Slam" in Melbourne, he contracted an illness before the tournament.

It threw him off his practice routine and contributed to the Spaniard's tweaking his hamstring in the quarterfinals.

That elusive 17th major for Federer looks like it will have to wait.


Can a new racket overcome his shoulder injury?

The positive news for Nadal is that his legs aren't the problem. He can still run around and play through the issue (unlike Federer in Doha). Slams are, of course, the best of five sets, and the champions' heart remains. It'd take an inspired opponent to eliminate Nadal prior to the quarterfinals, something that hasn't happened at a Grand Slam since the 2009 French Open.

His knees were indeed a culprit at Roland Garros three years ago, along with a damaged psyche (because of the split of his parents) and a sizzling Robin Soderling.

Nadal, thinking longer term, has turned to a new racket for more pop. As one might expect, he continues to adjust to the new stick. He was happy with his performance against Mikhail Youzhny in the Doha quarterfinals but then lost to Gael Monfils the next day.

What are his chances against Djokovic?

Nadal lost all six of his matches against Djokovic in 2011. Is it time for the law of averages to kick in?

Nadal has said he doesn't feel intimidated facing the Serb. Rather, it's a case of improving a few things. One of those is getting free points on serve, and that's where he hopes the new racket will come in handy.

Earlier this month, Nadal talked about the need to come to the net more often. To that end, he's been overly wary of Djokovic's scrambling and passing skills and has tended to stay put on the baseline, even when Djokovic is in trouble at the back of the court. Djokovic gets the ball back, a new rally begins and Djokovic usually prevails.

In the U.S. Open final, Nadal approached the net a mere 17 times -- but won 13 points. Djokovic, not as good of a volleyer, went to the net 47 times. When he had Nadal on the ropes in a rally, he ventured forward. At Wimbledon, Djokovic made 26 net approaches compared to Nadal's nine.

And as witnessed last year, Nadal's cross-court forehand gets eaten up by Djokovic's two-handed backhand.

What's the bottom line?

With Federer's health a question mark and Andy Murray still Slam-less, how can Nadal, even with the shoulder complaint and new racket, not be considered the second favorite behind Djokovic?

Regardless of the outcome Down Under, he'll have a nice, long break in February.

London-based Ravi Ubha covers soccer and tennis for ESPN.com. You can follow him on Twitter.