Boris Becker has refused to say whether he will still be on Novak Djokovic's coaching team past 2016.
Becker became Djokovic's head coach for the start of the 2014 season and, since working together, the German has contributed to six of the Serbian's 12 grand slam titles and 14 of his 30 masters 1000 titles.
However, Spanish spiritual guru Pepe Imaz was added to the team towards the back end of 2016 and he was in the box for the Paris Masters and season-ending event in London.
Recent reports have suggested there is some friction between the current coaching squad which also includes Slovakian Marian Vajda, although there has been no comment on this matter.
Djokovic endured a disappointing end to the campaign, losing his world number one ranking and ATP World Tour Finals crown to British star Andy Murray.
There are now doubts over Becker's future and he failed to confirm or deny whether he would still be involved with the Serbian for the 2017 season.
"We are in the process, but I can't tell you anything more than that," the six-time major winner told the Daily Mail. "I couldn't tell you yes and I couldn't tell you no."