The warning signs have been there for Chelsea since March 2014.
At the time it was easy to write off José Mourinho's criticisms as nothing more than the Portuguese taking a cursory dig at his players. But hindsight suggests he might have identified a problem that has festered at Stamford Bridge for almost five years.
“You have some players for everything and other players who are in their habitat in some circumstances,” Mourinho explained after his side had been beaten 1-0 by Crystal Palace.
“So, Stamford Bridge is better than away. Playing away against Arsenal or City or United or Liverpool is one thing, and another thing is to play Crystal Palace or Stoke away.”
Chelsea won the title the season after Mourinho's comments. Motivated and disciplined, the players proved they could take on the best in the Premier League and come out on top.
But the following season the Blues finished tenth. The blame, without substantial evidence to support it, was put on Mourinho, his abrasive management style viewed as out of touch with the modern-day player.
That belief was only heightened when Antonio Conte arrived in the summer of 2016. He guided Chelsea to the title in his first campaign in English football, again, though, one impressive, dominant season was followed up by mediocrity.
And almost four years to the day that Mourinho first questioned the Chelsea players, Conte did the same.
“I think our mentality must always be the same in every game; to try to get three points,” the Italian said. “That’s the only way if you want to succeed. We must have this mentality against every team we play.”
Conte left in the summer, Maurizio Sarri his replacement. Things started well, they usually do for Chelsea under a new coach. The Blues went unbeaten in their first 12 Premier League games, a record for a coach new to the English top flight.
The 12 league matches since, however, have been very different. Sarri's side have struggled to score goals, just the 13, have conceded frequently, 15 for those counting, and have lost five matches.
Defeat to Arsenal earlier this month was chastening, but it was Arsenal. The Gunners are challenging for a top-four spot and have elite quality in their ranks. While the performance was a major concern, the result could be understood.
Wednesday's loss at Bournemouth could not. Goalless at the break, Chelsea capitulated in the second period like no team has done since Roman Abramovich bought the club in 2003.
After the 4-0 embarrassment, Sarri spent 50 minutes dissecting the performance with his players in the dressing room. He then faced the media and delivered a similar message to that of Mourinho and Conte.
“We are doing something wrong with our mentality. We need to understand why and we need to react to the difficulty. For me, it's really difficult to understand why. I'm trying to do it, and I will try to do it tomorrow. It's not easy.”
Three different managers – two of which have won countless trophies and the other is regarded as one of the best coaches in Europe – have all questioned the Chelsea players' mental fragility. They can't all be wrong.
Of course, players have come and gone from Stamford Bridge over the years, and of the group Mourinho first questioned in 2014 only César Azpilicueta, Gary Cahill, Willian, Eden Hazard and David Luiz, either side of a spell with Paris Saint-Germain, remain.
Yet there seems an inherent vulnerability among the Blues squad. At the first sign of adversity, they crumble and leave the manager to take the blame.
Sarri fronted up after the Bournemouth defeat and accepted that, ultimately, it was his job to motivate the players. The Italian has made mistakes this season – his inflexibility is a problem, as is his continued use of underperforming players which underpins his unwillingness to rotate – but the underlying issues are not his doing.
The Chelsea dressing room has not been an easy one to manage over the years. Big personalities – the likes of Petr Čech, John Terry, Frank Lampard, Didier Drogba – reigned. Was it a healthy culture? Probably not. But as long as the club constantly challenged for titles and reached the latter stages of the Champions League it could be excused.
The Chelsea of 2019 is very different. The Blues are not battling for the title and they are not even in the Champions League. The culture remains the same, though. Poor results are blamed on the coach, information undermining him is leaked to the press.
That's what has happened after the defeat to Bournemouth; a report in The Telegraph stating Sarri criticised Hazard for not following instructions and that the players find training too repetitive as the Italian attempts to drill them in his style of football.
Conte had the same problem; reports last season claimed the player found his sessions boring. But without the repetition, how do Chelsea's players expect to grasp the intricacies of Sarri's system?
“We haven’t even learned the most basic moves yet,” the Italian admitted on Wednesday. “We need to work on the basics, the primary foundations of my football, and only then will we try to change a few things.”
Chelsea knew what they were getting when they hired Sarri in the summer. He has his vision, or to use a football buzzword, philosophy, and he isn't going to change that. If Plan A isn't working, his Plan B is to make Plan A work.
It's rigid, stubborn and dogmatic, but ‘Sarri-ball' worked at Napoli because the players bought into it wholeheartedly. It's had its moments at Chelsea, too, when the players have been motivated – only last week the Blues overawed an admittedly weak Tottenham side to reach the League Cup final.
This inconsistency has plagued Chelsea for too long. And it can't be allowed to continue. It is time the club go all in on a coach and live with the ramifications, and they could do a lot worse than Sarri.