Djokovic failed to win a title from August onwards -- after claiming six in the first half of the campaign -- and relinquished top spot in the world rankings to Andy Murray.
He admitted to losing his motivation for a while and suffering from "private issues," while wrist and arm injuries also played a part in his slump.
The Serb ended his season with a crushing loss to Murray in the final of the ATP World Tour Finals, with the No. 1 spot on the line, despite the Scot playing a nearly four-hour match the day before.
Rafter, though, is convinced the 29-year-old will rediscover his form and add to his tally of 12 majors next season.
"Djokovic will have a half-decent year again and win a couple slams," the Australian told CNN's Open Court.
Djokovic, according to two-time US Open winner Rafter, has the potential to reclaim the top ranking.
Djokovic, according to two-time US Open winner Rafter, has the potential to reclaim the top ranking.
Winning two majors would certainly help his cause.
By contrast, Rafter isn't sure if Murray will be able to replicate his outstanding 2016.
"Will he be able to solidify it? I don't know," Rafter said of the Brit.
