MOST people tend to agree that one of the key problems at Sunderland in the last few years has been the lack of any stability.

A tally of five managers in less than four years – six if you include the three-game caretaker spell of Kevin Ball – smacks of constant upheaval, with the chaotic installation and then rapid removal of Roberto De Fanti as director of football adding even more volatility to the mix.

The players, so common consensus agrees, haven’t known whether they’ve been coming or going, and whereas other clubs have developed a prevailing methodology that survives managerial changes, the mood at Sunderland has swung wildly depending on who is in charge.

There is undoubtedly merit to this argument, and when Ellis Short appoints a new permanent head coach in the summer, it is to be hoped he does so with the avowed intention of putting an end to the constant churn that has come to characterise his reign.

Yet even accepting all of that, there is perhaps one area where more change rather than less would be desirable. Dick Advocaat was quoted in the Dutch press on Wednesday as saying, “We have a decent team, if everyone is fit. But John O’Shea and Sebastian Larsson for instance, who have not trained this week, will need to play on Saturday because the group is quite small.” Damningly, Steve Bruce some three-and-a-half years ago might have been saying exactly the same.

Take a look at the side that started Bruce’s final game in charge of Sunderland, a match that had stark parallels to last weekend’s defeat to Aston Villa that hastened the demise of Gus Poyet, and there on the team sheet are the names of both O’Shea and Larsson.

Playing alongside O’Shea at the heart of the back four? Wes Brown. Tomorrow, there’s every chance the pair will be back together at West Ham. Lee Cattermole was the defensive linchpin in November 2011, just as he would be tomorrow were he available.

Further forward, Connor Wickham didn’t make the starting line-up against Wigan, but he did manage 19 appearances during his first season on Sunderland’s books. Steven Fletcher and Adam Johnson weren’t available under Bruce, but they arrived nine months later in an overhaul overseen by Martin O’Neill.

So by the middle of 2012, the spine of Sunderland’s side featured O’Shea, Brown, Cattermole, Larsson, Johnson, Fletcher and Wickham. And there we were thinking the Black Cats were continually being turned upside down.

Individually, all seven of the players mentioned have their merits, but collectively it is hard to describe them as anything other than a failure. Since the transfer window in the middle of 2012, Sunderland have finished 17th, 14th (having been in 20th until three games before the end of the season) and now find themselves back in 17th. They have played 105 league games, and won 23.

They have now been through four different managerial regimes, yet the core of the side has remained largely unaltered. It is not as though potential replacements have not been signed – 16 players arrived in one especially chaotic summer under De Fanti – but despite an enduring lack of achievement, the same faces continue to play the same prominent role.

They continue to fill key positions in the team, albeit with Fletcher and Wickham’s importance having been diminished slightly following the signing of Jermain Defoe, and are powerful influences within the dressing room. O’Shea is club captain, with Cattermole tending to stand in for him when he is not available.

As a collective, they are the constant that runs through Sunderland’s various struggles and, if anything, they are probably more important now than ever. One imagines Advocaat will turn to experience over the course of the next nine games, and that will inevitably mean having to go back to players who have failed in the past.

The fact they remain so integral is a damning indictment of Sunderland’s signing policy, and among all the changes that will occur this summer, there is a clear need for a radical overhaul of the club’s scouting and recruitment process. Too many recent decisions have appeared haphazard; too many sub-standard players have arrived for substantial fees.

But as well as signing the wrong players, the constant battles against the drop suggest the Black Cats have also been holding on to some of the wrong ones too. That is unlikely to change any time soon, as in the last five months, O’Shea and Wickham have signed new two and four-year deals respectively.

That is not to suggest they were not worthy of those deals, although O’Shea’s age has to be a factor for discussion, and if you were to strip out four or five senior players in one go, that would clearly leave a huge gap that would be both expensive and difficult to fill.

But the fact remains that whoever takes over Sunderland on a permanent basis next summer will find themselves presiding over a group of players who have grown accustomed to scraping around in the bottom half of the table.

Their frailties have been exposed on numerous occasions in the past, yet they will form the core of a squad that will be expected to make significant progress towards establishing themselves in the top half of the table.

Perhaps, with better coaching and organisation, they will be able to achieve that. Perhaps Sunderland’s last four managers have all been so compromised that the players working under them were never able to realise their potential.

Short, in particular, must hope that is the case, because otherwise it is difficult to see how the ongoing cycle of underachievement will be broken. Albert Einstein defined insanity as doing the same thing over and over again, and expecting a different result. Sadly, for all the change in certain areas, Sunderland are proving the wisdom of his words.