Newcastle United players believe they are paying the price for recruitment gambles amid uncertainty over whether or not head coach Matthias Jaissle can successfully lead the club’s rebuild.

Jaissle accused his players of failing to follow his game plan after the defeat by Everton that prompted boos from Newcastle supporters.

But Telegraph Sport has been told there is a feeling in the dressing-room that Newcastle’s recruitment is the biggest reason behind the club’s early-season struggles.

That is said to be coupled with uncertainty over whether or not Jaissle, in his first season in English football, can adapt his approach to steer Newcastle through a period of change.

Jaissle is generally well liked by Newcastle’s players and is said to be collaborative in his approach, but the 38-year-old is yet to adjust his methods to help the team pick up points.

There is no overriding desire within the Newcastle dressing-room for a change of head coach and players accept responsibility for below-par performances. But there is a belief they have been left hamstrung by the club’s recruitment and that changes to Jaissle’s set-up could benefit them.

Newcastle are 13th in the Premier League table and were knocked out of the League Cup by Everton last week.

Jaissle’s assessment that his Newcastle players launched too many long balls in Monday night’s league defeat to Everton may cause some confusion, given the German is said to have instructed his team to play the game in the opposition half as much as possible for most of this season.

The situation at Newcastle has echoes of the dressing-room complaints at Manchester United, where Lisandro Martínez criticised the club’s recruitment strategy and Bruno Fernandes raised doubts over head coach Michael Carrick.

Concerned Newcastle players have not voiced their opinions publicly and the feeling on Tyneside is not thought to be as aggressive or toxic as the apparent divisions within Old Trafford. But doubts have been creeping in since a summer in which Newcastle missed out on a host of players and gambled on a number of signings unproven in the Premier League.

Having lost three of the club’s best players in Bruno Guimarães, Sandro Tonali and Anthony Gordon, Newcastle spent around £262.9m on eight new signings this summer who were meant to reinvigorate the squad.

But Aladji Bamba, Bazoumana Touré and Matías Fernández-Pardo have failed to make any sort of impact yet, while Sean Steur will need time and Amar Dedic and goalkeeper Lukasz Hornicek have made some costly errors, despite also producing some encouraging performances.

One source said: “It’s not that they are necessarily bad players, but they aren’t ready for the Premier League. You can’t rely on them yet. Put that together with a manager who hasn’t coached in England before and it is a dangerous mix.”

Ross Wilson, Newcastle’s sporting director, oversaw summer transfer activity but the club’s recruitment issues also pre-date him to last summer when mistakes were made over Nick Woltemade and Yoane Wissa.

There was a lack of identity over Newcastle’s recruitment before this summer, when the club attempted to lower the average age of the squad. But that approach has, so far at least, come at a cost in terms of consistency and results.

Jaissle’s approach has prompted some comparisons to Rúben Amorim’s time at Manchester United, when the Portuguese failed to adapt his methods to suit his squad and nullify the opposition.

Whereas Amorim stuck with a back three to disastrous effect at United, Jaissle has left his Newcastle midfield exposed by trying to crowbar a number of players into a number 10 role.

Newcastle have been consistently overrun in midfield this season and a source said: “It’s been obvious that the team needs another body in midfield, but the manager has stuck with two and then a number 10. It just looks a bit naive when it hasn’t worked and he has to be careful it doesn’t end up like Amorim at Man United.”

Jaissle must now prepare for Newcastle’s trip to Fulham, where a defeat would put him under further scrutiny, going into the international break.

This is Jaissle’s sink-or-swim moment

We are three months into Jaissle’s reign as Newcastle United manager and it is not over the top to suggest he will not last another three if things do not improve rapidly.

This is his sink-or-swim moment. Is he out of his depth and going to be dragged under, or is Jaissle made of sterner stuff? Can he stabilise things, cope with his first crisis of confidence and belief, and lead the team out of these choppy waters? We are about to find out.

Newcastle travel to Fulham on Saturday and after the international break they face Arsenal, Brighton, Manchester United and Sunderland. If Jaissle does not win any of those games he will surely be on the brink of the sack.

Although sources have denied his presence means anything significant, Jacobo Solis, PIF’s most hands-on representative on the board, has been on Tyneside for more than a week. He even sat at the back of a Jaissle press conference last week.

He has been holding meetings with all the key figures at the club and will be reporting back what he hears and sees to Riyadh. He will not have been impressed by what he saw at St James’ Park on Monday night.

If Jaissle loses to Sunderland, the damage may be irreparable. Eddie Howe lost twice to their bitter rivals last season and even with his fantastic record over four years and so much goodwill in the bank, he failed to recover.

This was always going to be a tough job and whoever replaced Howe was going to find it hard to live up to expectations. The real concern is that the grumblings in the stands are being echoed in the dressing room.

There are doubts about this young manager’s ability to lead the team in the Premier League and his “vertical football” philosophy. There is also internal criticism of the summer signings. Newcastle’s rebuild focused on “future stars” after selling their three best players to fund it.

None of the new signings have impressed consistently. Of the three who started the miserable defeat to Everton, Nico Gonzalez was cumbersome and hooked midway through the second half. Amar Dedic was given the runaround for the second successive game and goalkeeper Lukas Hornicek was at fault for the goal.

Jaissle clearly does not trust Bazoumane Toure – who came on in the 87th minute – Aldji Bamba – unused sub – and Sean Steur – who replaced Gonzalez – to start games. If the players are critical of the summer recruitment, the manager’s team selections suggest he does not believe in it either.

I have been saying it for weeks. Newcastle are a poor team playing badly. All the worst fears of the summer – warnings from those of us who have been covering this club for more than two decades – are morphing into grim reality.

There was anger inside St James’ Park as the team limped its way to a dross defeat, but, worse than that, there was apathy. This was a performance from the Mike Ashley era, but the lack of atmosphere inside the stadium should worry those at the top.

For the first time in years, you could still get tickets for the game on matchday. Newcastle fans are drained and deflated. They are starting to wonder whether this team, playing such ugly and disjointed long-ball football, is still worthy of their passionate and unflinching support.

We have not heard a Newcastle team booed and whistled at St James’ Park since the bleak, dark days of the Steve Bruce era.

Nevertheless, it is nothing new when underperforming players moan about a manager when the team is losing.

These are tough times and the pressure is on, but Newcastle won at Crystal Palace less than a fortnight ago. They would have been seventh if they had beaten Everton and had the chances to secure a point. Anthony Elanga and Yoane Wissa missed huge chances late on.

These are senior players and they are letting the team and supporters down. It’s not just the missed chances, it is their overall performances. Harvey Barnes was another who was really poor for a second consecutive game. While Jacob Ramsey, on as a late sub, had only one contribution: picking up two yellow cards in 86 seconds of stoppage time and earning a one-game suspension.

Jaissle is under pressure and the club is in danger of splintering, but he has barely had time to get his ideas across. Three months is not long enough to judge a manager, particularly as he had no influence over recruitment before his arrival.

He will either thrive or flounder over the next couple of months. Time is a precious commodity for any manager. Jaissle must make the most of what he has on the training ground. If he does not, it will run out for him. It is a brutal world and the only place his vertical football is taking Newcastle is down the Premier League table. He has to reverse the decline quickly.