When tennis fans consider how the rest of 2018 will unfold, a number of things are expected: that Rafael Nadal will dominate on clay, that Roger Federer will carry on defying time, and that Andy Murray will come back hungry and determined to recapture his best form.
However, questions continue to dog the other member of the big four, Novak Djokovic. When he completed the set of Grand Slams by winning the 2016 French Open title, he had 12 Grand Slams to his name and many wondered if he would go on to overtake the tallies won by Federer and Nadal.
Since then, however, he has reached just one Grand Slam final - the 2016 US Open, where he lost to Stan Wawrinka - and has been beset by injuries, a loss of form and conflicts with coaches.
Like Murray with Ivan Lendl and Federer with Stefan Edberg, Djokovic has been down the route of employing great ex-players. Under Boris Becker he reached new heights, but at the end of 2016 the German moved on, suggesting the Serb had lost some of his hunger and focus after that French Open triumph.
Becker is now in good company, because Djokovic has now parted company with Andre Agassi, as well as his head coach Radek Stepanek, in another shake-up of his team. Agassi revealed the partnership simply didn't work, saying: "With only the best intentions, I tried to help Novak. We far too often found ourselves agreeing to disagree."
Some might conclude that Djokovic is fading away and that nothing much can be done about it, whoever coaches him. Fans booking corporate hospitality for the Championships, Wimbledon will hope otherwise, however, having seen some brilliant tennis down the years from the three-time winner.
Indeed, the player himself has indicated that he is still as keen as ever to perform well. A statement on his personal website said: "Novak remains focused and eager to come back stronger and more resilient from [a] long injury break that has affected his confidence and game.
"He is continuously and passionately looking for new and different ways to regain winning form."
With Federer and Nadal threatening to dominate this year as much as the last, many would be delighted to see Djokovic return to his best. It may be that the coach with the right formula is not a former legend at all, but someone who has the kind of motivational skills to enable Djokovic to work through the finer details of his game.
If the former world number one cannot come back, the focus may be increasingly on what Murray can achieve against Federer and Nadal, as well as the prospects for Marin Cilic and the in-form Juan Martin del Potro, whose recent hot run ended in the Miami final against John Isner. It may also open the door for Alex Zverev, if he can finally demonstrate his precocious talent in Grand Slams.
However, even if all those players can illuminate the rest of 2018, many would still feel sad if the career of one of the undoubted all-time greats was just to fade away. Having seen the way Federer and Nadal came back after being written off, however, few would be willing to pen any career obituaries for Djokovic just yet.
Image: Julian Finney/Getty Images from Keith Prowse subscription