Nadal is currently ranked number 9, while Federer has dropped to 16 in the ATP rankings.
Nadal cut his 2016 season short after the Shanghai Masters in October.
Nadal will make his injury comeback at the Mubadala World Tennis Championships in December.
Becker has backed Djokovic to bounce back in the 2017 season.
The world number one is not expecting to attend Sports Personality of the Year ceremony on 18 December.
Murray ended the 2016 season as the World No 1 after lifting first ATP World Tour Finals crown.
The Scot is the year-end world number one for 2016 after dominating his great rival over the season.
Murray registered his 24th straight win after defeating Djokovic at ATP World Tour Finals.
The world number two says lack of court time hindered his attempts to win sixth title in London.
Year-end world number one planning quiet dinner to mark victory at ATP World Tour Finals.
The 29-year-old defeats Djokovic 6-3 6-4 to win maiden title at season-ending tour finals.
Nadal is expected to return to tennis at the Mubadala World Tennis Championships in December.
The battle for the year-end world number one comes down to the last match of 2016.
Defending champion remains in contention for year-end world number one after dominating Kei Nishikori.
World number one wins 5-7 7-6 7-6 in match lasting three hours and 38 minutes at The O2 Arena
All the information Djokovic and Nishikori battle to reach the final at tour finals in London.
All the information as Murray seeks to reach maiden final at tour finals in London.
Djokovic has not won a title since the Rogers Cup in July.
Murray is currently in action at the ATP World Tour Finals event in London.
Japan number one warms up for semi-final with three-set loss at The O2 Arena
World number one books semi-final with Milos Raonic after 6-4 6-2 victory in London.
Defeat for Herbert and Mahut sees Australian and US Open winners Murray and Bruno Soares top rankings.
All the information ahead of the final round robin match at the season-ending tour finals in London.
Novak Djokovic has progressed into the semi-finals of the ATP World Tour Finals.
All the information as Murray looks to book semi-final place at tour finals in London.
Federer has not played since his semi-final loss to Raonic at the 2016 Wimbledon in July.
Canadian joins Novak Djokovic in the semi-finals after straight sets victory.
The world number two wins 6-1 6-2 - but sees red for the second time this week at The O2 Arena.
All the information ahead of day five at the season-ending tour finals at The O2 Arena in London.
All the information ahead of day five at the season-ending tour finals at The O2 Arena in London.