Three tournaments, starting Sunday with the Brisbane International, open the season and the preparation period ahead of the Australian Open. Events in Qatar and India begin Dec. 30.
The Australian Open runs Jan. 13-26, giving players just two weeks of competition before the year's first major tournament.
Djokovic is a three-time defending champion at the Australian Open. No one else has won more than two consecutive Australian Opens since Roy Emerson won five straight (1963-67). The only other winner of three straight was Jack Crawford (1931-33).
Nadal won the 2009 Australian Open and was a finalist -- losing in five sets to Djokovic -- in 2012 but he's been as far as the semifinals only one other time.
The year opens with the two players dominating the rankings. Nadal, who won the French Open and U.S. Open in 2013, has 13,030 points and doesn't defend any points until February. Djokovic, who was runner-up at Wimbledon (to Andy Murray) and the U.S. Open, has 12,260. No. 3-ranked David Ferrer opens the year with 5,800 points, more than 6,000 behind Djokovic.
The ATP Top 10 listing player's name, home country and rankings points:
1. Rafael Nadal, Spain, 13,030
2. Novak Djokovic, Serbia, 12,260
3. David Ferrer, Spain, 5,800
4. Andy Murray, Great Britain, 5,790
5. Juan Martin Del Potro, Argentina, 5,255
6. Roger Federer, Switzerland, 4,205
7. Tomas Berdych, Czech Republic, 4,180
8. Stanislas Wawrinka, Switzerland, 3,730
9. Richard Gasquet, France, 3,300
10. Jo-Wilfried Tsonga, France, 3,065