We are already four months into the campaign, and a lot has happened since things kicked off in earnest in August.

In the Premier League alone, six managers have been relieved of their duties, while Newcastle United have been taken over by PIF.

They, along with other clubs, will surely be busy in the January transfer window. However, new arrivals are not always guaranteed to be successful – you only need to look back to the summer to see that.

But who have been the biggest transfer disappointments of the season so far? Read on to find out.

Nikola Vlasic

After leaving Everton in 2018, Vlasic developed into a goalscoring threat at CSKA Moscow, netting 33 times in 108 games from the middle of the park.

Nikola Vlasic at West Ham

That convinced the Hammers to part ways with £26.8 million, plus £7.7m in add-ons, to take him to the London Stadium. However, the Croatia international has struggled to break into David Moyes' side, starting just a single Premier League game so far. Given the lack of options behind Michail Antonio up front, that money should probably have been spent on a back-up striker.

Emiliano Buendia

During Norwich's last ill-fated Premier League term, Buendia was arguably the Canaries' brightest light as they finished bottom of the table. A stupendous Championship season followed – he was voted the division's Player of the Season after scoring 15 times and providing 17 assists – meaning the record £33m Aston Villa paid for his services in the summer looked a relatively good deal.

Emiliano Buendia at Aston Villa

So far, he has failed to show what all the fuss is about. Just one goal and one assist have come in 11 league outings, and he has not played more than 75 minutes in a game since August. In Steven Gerrard's first two matches, he did not impress despite featuring in both victories, albeit once from the bench.

Bryan Gil

Admittedly, Gil's signing is one for the long-term, but he has played enough this campaign for his performances to be questioned.

Giveaway

ENTER GIVEAWAY

It has not been an easy season for anyone at Spurs. Gil, however, comes from Sevilla with a strong pedigree, yet he has been unable to show that in north London. Most worryingly, six of his seven starts in all competitions have come in the UEFA Europa Conference League against inferior opposition such as Slovenian minnows NS Mura. Gil has failed to stand out in any and, given Antonio Conte's general reluctance to deploy developing players, it could be a long season for the 20-year-old.

Milot Rashica

According to Transfermarkt, Rashica is Norwich's joint-record signing at £9.9m. While that is not a particularly large fee compared to other Premier League deals, it heaps relatively big expectations onto his shoulders.

Milot Rashica at Norwich

Ultimately, the Kosovo international was part of a dire Werder Bremen side that was relegated from the Bundesliga last term, and he could well make it back-to-back demotions this term. He has been disappointing on the left flank, unable to use his pace and trickery to any real effect, and must do more if he expects to remain in Dean Smith's plans.

Jadon Sancho

Manchester United spent the best part of two years trying to sign Sancho from Borussia Dortmund, where he blossomed into a star, and finally got their man in the summer. They paid £73m for his services, which looked a bargain considering they were quoted over £100m 12 months prior.

Jadon Sancho at Manchester United

The 21-year-old's showings so far, therefore, have wholly underwhelmed. Shackled by Ole Gunnar Solskjaer, who seemed unaware of how to use him, the England international didn't score or provide an assist until last week against Villarreal, the first game following Solskjaer's departure. Another goal against Chelsea at the weekend suggests he may have turned a corner, but he has to do a whole lot more to justify his hefty price tag.

Joe Willock

Eight goals in 14 matches on loan at St. James' Park last season convinced even Mike Ashley to dip into his pockets and part with £25m to sign Willock permanently.

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So far, that form looks like a false alarm. The Magpies are yet to win a single game this season in the Premier League, and Willock's goalscoring powers seem to have abandoned him. In January, the news owners will undoubtedly be busy in the transfer market and, if Willock does not start to perform, he may be in danger of losing his place in the starting XI to a new arrival.

Jack Grealish

A lot was expected of Grealish given Manchester City parted with £100m for the first time to capture the England international.

Jack Grealish at Manchester City

His time at the Etihad Stadium cannot be called a disaster, but two goals and three assists in 15 matches are hardly befitting of the hype around his signature. After all, he was billed as the answer to England's prayers at Euro 2020, even as the Three Lions reached the final and only lost on penalties. Pep Guardiola has admitted he needs to see more from the 26-year-old and, although City's strength in depth has glossed over his difficulties, it is time for Grealish to deliver.

Saul

Saul only moved to Chelsea on loan in the summer, making his signing of minimal risk to the Blues. Still, the disparity between the Spain international's reputation and his poor start to life at Stamford Bridge earns him a spot on this list.

Saul Niguez at Chelsea

After all, he has been a key member of Diego Simeone's side over the past seven years, winning La Liga and two Europa Leagues. However, he has spectacularly struggled to adapt to the increased pace of the Premier League, which even Thomas Tuchal has admitted. He only has 47 top-flight minutes to his name so far and, of the three games he has started, Chelsea have won just one in normal time. The London outfit do have a £30m option to make the deal permanent, but it would be a surprise to see them exercise it on this form.

Dan James

Parallels could be drawn between James' move to Leeds and Sancho's to United's. The Wales international, too, was courted for a considerable time before finally switching to Elland Road.

Daniel James at Leeds United

Following his first performances for the club, Marcelo Bielsa may be wondering why he bothered with his vigorous pursuit. 13 appearances have brought one goal and one assist, and the 24-year-old has struggled to display the technical efficiency needed for a Bielsa side. Time is on his side, of course, although Leeds need him to start shining relatively quickly as they aim to move away from the relegation zone.

Worst of the rest

Donyell Malen

Filling Sancho's shoes was always going to be a daunting task for Malen, and he has far struggled to do so regularly.

Donyell Malen

There have been glimpses of his ability, such as a well-taken finish against Wolfsburg last week, but those moments have been exceptions rather than the rule. As it stands, the Schwarzgelben are just one point behind Bayern in the Bundesliga table and, if they want to give the reigning holders a run for their money, Dortmund need Malen firing on all cylinders.

Andre Silva

Last season, Silva was one of Europe's breakout stars at Eintracht Frankfurt, scoring 28 goals in 32 Bundesliga appearances as the 'Adler' finished fifth in the table. It was, therefore, unsurprising to see RB Leipzig swoop for the forward as they looked to replace Timo Werner 12 months after his departure.

However, under new boss Jesse Marsch, Leipzig have struggled, and Silva's own difficulties have been emblematic of their season so far. Five goals in 20 appearances are not what was excepted when the Rotenbullen completed his signature. Already 13 points behind league leaders Bayern, a title challenge seems out of the question – now, it is about salvaging a place in the Champions League next term, and Silva can still turn his season around.

Georginio Wijnaldum

Wijnaldum ended a five-year association with Liverpool during the summer, leaving on a free transfer and deciding to seek a new challenge. He was one of Jurgen Klopp's most trusted players as they won the Champions League and Premier League, and the Netherlands international will have no doubt expected to walk into Paris Saint-Germain's side after moving to the Parc des Princes.

Georginio Wijnaldum at PSG

The reality, however, has been different. The 31-year-old has started just eight of PSG's 14 Ligue 1 games and, despite being given a more attacking role by Mauricio Pochettino, has just two goals in 18 outings in all competitions. He has already suggested he is not totally happy in Paris and has even been linked with a return to former club Newcastle. Sometimes, the grass isn't greener.