For Roger Federer to regain the world No. 1 ranking, he will have to follow a carefully constructed blueprint while playing the best tennis he can muster.
Of that trio, Nadal is the least likely to climb to the World No. 1 spot due to a left-knee ailment that forced him to miss the second half of the 2012 season. Nadal has spoken about limiting the number of hard-court events that he enters, as the Spaniard's knees cannot handle playing on the surface too often.
Murray is currently ranked one spot behind Federer but is expected to be more of a year-round threat in 2013 now that he is a Grand Slam champion. Also, at just 25 years of age, Murray is at his peak physically and will play in more events than Fed.
However, Federer's biggest obstacle to get back to No. 1 is Djokovic, as the Serbian is currently in the top spot and has played brilliant tennis over the past two years.
The road back to No. 1 promises to be treacherous, but after an unlikely return to the top spot last season, Federer should not be counted out.
This one can go without saying, as Roger Federer will need to stay healthy and win tennis matches in order to regain the world No. 1 ranking.
Federer's career has been defined by his durability, as he has not missed a Grand Slam tournament since he claimed his maiden title at Wimbledon in 2003.
Outside of a bout with mononucleosis in early 2008, Fed-Ex has been able to stay healthy throughout the entirety of his prime. Considering the brutal nature of the tour, Federer's durability is nothing short of exceptional.
Roger's durability is in stark contrast with that of Rafael Nadal, as Federer's chief rival will likely see his career shortened due to his shaky knees.
Roger Federer could have found success in any era, partially because of his ability to serve and volley. For that reason, he would have been able to compete against past legends on quicker courts.
According to SportsIllustrated.com, Boris Becker said the following in regard to Federer and his contemporaries competing in Becker's era:
I don’t think [Rafael] Nadal or [Novak] Djokovic would have been so successful in the era of serve and volley, but Federer could have played. The reason why Federer is still successful at the age of 31 is because he has got a good technique. He can play from the baseline and when he has to, he can also come to the net more often than other players.
In today's game, players are able to control the ball like never before. The advancements in racket and string technology, along with the decision to slow down the courts across the tour, has changed the game of tennis irrevocably.
Even though serving and volleying doesn't provide the advantage that it used to, Federer should utilize the strategy more because of his superb net play.
When Fed follows his serve to the net, he takes time away from the accurate baseline strikers who dominate the tour. The change of pace also puts the opposition in a state of unease while returning because they have to account for Federer charging to the net.
Roger Federer is 31 years old, even if he moves like a much younger man. While his play has not slipped much, his body needs more time to recuperate than it used to, and he's at a greater risk of injuries when fatigued.
If Federer truly wants to play until the 2016 Rio Summer Olympics—something he has stated he wants to do—he has no choice but to cut down on his schedule to limit the wear and tear that a grueling season inflicts on his body.
In order to regain the No. 1 ranking, Federer must focus his attention on the Grand Slams, and to a lesser extent, the ATP Masters 1000 tournaments. While the world's top players focus on the biggest events anyway, Federer will not be entering as many Masters events as he has in the past.
Federer has already began to cut events from his schedule to ensure peak performance, as he left the Masters series tournament in Miami and the ATP 500 event in his hometown in Basel off his 2013 schedule.
Since he is entering fewer tournaments, Federer will be under more pressure to achieve good results on a consistent basis. With fewer events on his schedule, an early loss will stunt his ascent up the rankings more than it would in seasons past.
Of the world's top four players, Roger Federer had the worst winning percentage on opponent's second-serve points in 2012. Novak Djokovic, Andy Murray and Rafael Nadal were the top three in the world in terms of second-serve return points won, while Federer finished No. 14 in the category.
Federer has been able to overcome his returning problems by being extremely efficient on his own serve. He held serve on 91 percent of his service games in 2012, which was a higher holding percentage than that of his three rivals.
On days when Federer's serve is off, he has trouble competing against the world's elite returners. During these off days especially, Fed-Ex should be more aggressive on his second-serve returns, because they represent an opportunity for him to gain control of the point from the get-go.
Federer is at his best when playing aggressively, so he should look to take control of the match whenever possible.
Roger Federer will have to be in possession of two Grand Slam titles to regain the world No. 1 ranking due to the lighter schedule he will play in 2013.
Andy Murray and Novak Djokovic, who will be Federer's fiercest rivals in his chase for the top ranking, will be entering more events in the coming year than the all-time Grand Slam champion.
This means Federer must thrive in the Slams, because they are worth the most ranking points. Winning a major yields 2,000 points, and Federer is currently trailing the top-ranked "Djoker" by 2,655 points.
Out of the four majors, Federer will be hard pressed to win another French Open, as Rafael Nadal will be the overwhelming favorite if healthy.
Fed-Ex's best chances to win Slams will be at Wimbledon and the U.S. Open, but he will have to muster his best tennis at both events in order to hoist the winner's trophy.
Federer has not won in New York since 2008, as he has failed to overcome the field's young challengers in recent years.
When Wimbledon rolls around next season, Federer will have nothing to gain, as he will be tasked with defending his 2012 victory.
At the Australian Open, Federer will be among the favorites but would be viewed as an underdog if he were to meet Djokovic in the semifinals or finals.
Federer has not won two Grand Slams in the same calendar year since 2009 but will look to change that in 2013.