Even the world's biggest clubs can get it horribly wrong in the transfer market, and Chelsea are no exception.
The Blues have signed many a star player in their history; they've also acquired some absolute duds.
Here, we take a look back through the worst deals the West London club have ever done.
35. Kepa Arrizabalaga
There were spells when Kepa Arrizabalaga looked like the elite goalkeeper Chelsea thought they were getting when they paid Athletic Bilbao a world-record £72m in 2018.
Unfortunately, the Spaniard will mostly be remembered at Stamford Bridge for sub-par performances between the sticks – and refusing to be substituted by Maurizio Sarri in the 2019 League Cup final.
34. Shaun Wright-Phillips
Signed a matter of months after Jose Mourinho's Chelsea had secured their first Premier League title in 2005, Shaun Wright-Phillips had emerged as a 17-year-old at Manchester City and rapidly established himself in the first team.
And the England winger's first few seasons at Stamford Bridge went well enough – but, despite becoming a Premier League champion in 2005/06, he never really lived up to his £21m price tag and he re-joined City in the summer of 2008.
33. David Datro Fofana
Chelsea signed 20-year-old Ivory Coast international striker David Datro Fofana on a six-year deal in January 2023 – then loaned him out to Union Berlin after only four appearances.
What's more, the Blues then went and signed two further, more established centre-forwards during the same window in which they sent Fofana away on loan. Did they think this one through properly?
32. Marc Cucurella
Marc Cucurella enjoyed a fine first season in English football with Brighton, but more than a few eyebrows were raised when Chelsea moved for the Spanish left-back in a deal worth up to £62m in August 2022.
Such a price tag brings pressure to deliver – and Cucurella did not, despite soon being reunited with his old boss Graham Potter (well, for all of his six-month tenure as Blues head coach).
31. Franco Di Santo
Franco Di Santo scored only 14 goals in 92 Premier League appearances – and not a single one of those 14 came for Chelsea, who the Argentine striker joined from Chilean outfit Audax Italiano in January 2008.
Di Santo never made the grade at Stamford Bridge, though, leaving for Wigan Athletic in 2010 having failed to find the net in 16 outings in all competitions for the Blues.
30. Youri Zhirkov
One of a handful of Russian signings made during Roman Abramovich's ownership, Yuri Zhirkov cost Chelsea £18m from CSKA Moscow in July 2009.
That made the left-back the most expensive Russian player of all time – but he failed to make his mark on the Premier League (although he did collect a winners medal as a member of Carlo Ancelotti's 2009/10 title-winning squad).
29. Pierluigi Casiraghi
Italian frontman Pierluigi Casiraghi joined Chelsea from Lazio in May 1998 – and suffered what proved to be a career-ending knee injury just six months later, in a collision with West Ham goalkeeper Shaka Hislop.
After a string of unsuccessful operations, the Blues terminated Casiraghi's contract in the summer of 2000 – with the player subsequently exploring legal action against them, suggesting that he was owed £2.5m in unpaid wages.
28. Quique de Lucas
Chelsea became Quique de Lucas' third club in the space of 12 months when he arrived at Stamford Bridge as a free agent in the summer of 2022 – and you could forgive Blues fans for forgetting he ever played for the club.
The Spanish midfielder only featured here and there for Claudio Rainieri's side, returning to his homeland to sign for Deportivo Alaves at the end of the 2002/03 campaign.
27. Slobodan Rajkovic
[CHANGE POSITION]
Slobodan Rajkovic was a Chelsea player for four years – only he wasn't really: the Serbian centre-back, signed from OFK Beograd aged 16, never actually played a competitive game for the Blues.
Instead, his action between 2007 and 2011 came on loan at Eredivise clubs PSV, Twente and Vitesse Arnhem, before he left Stamford Bridge permanently for Hamburg.
26. Jiri Jarosik
If you were asked to name every player from Chelsea's 2004/05 Premier League-winning squad, you probably wouldn't remember Jiri Jarosik – and we can't say we'd blame you.
A January 2005 arrival from CSKA Moscow, the Czech defender – who was once sent on as a substitute by Jose Mourinho with a note for teammate Tiago – left the Blues the following year, having made only 14 league appearances.
25. Michy Batshuayi
Michy Batshuayi made 77 appearances for Chelsea – and 73 during previous loan spells away from the club where he failed to make much of a splash.
Signed for £33.2m in July 2016 off the back of a 23-goal season for Marseille, Batshuayi was the first arrival of the Antonio Conte era at Stamford Bridge – and the hope was that he'd fire the Blues to glory.
And Chelsea did win the 2016/17 Premier League in title – although largely because of Diego Costa's 20 goals, not Batshuayi's five...
24. Tal Ben Haim
Three strong seasons for Sam Allardyce's upwardly mobile Bolton Wanderers saw Tal Ben Haim catch the eye of Chelsea, who signed the Israeli centre-back as a free agent in the summer of 2007.
Ben Haim was unable to make the step up in quality, however, and left the club after 12 months – having landed himself in hot water for publicly slating manager Avram Grant, the successor to the man who signed him: Jose Mourinho.
23. Khalid Boulahrouz
Perhaps best remembered for wearing Chelsea's number nine shirt despite being a defender, Khalid Boulahrouz endured a pretty miserable time of things at Stamford Bridge.
Signed from Hamburg in August 2006, the Dutchman started brightly for the Blues but ultimately made only 13 Premier League appearances before going out on loan to Sevilla the following season.
22. Scott Parker
A legend at Charlton Athletic, where he had risen through the youth ranks to become the star man in Alan Curbishley's side, Scott Parker moved from South East to West London to join Chelsea in January 2004.
Things were looking rather rosy for the England midfielder as he scooped the 2003/04 PFA Young Player of the Year award, but the arrival of Jose Mourinho that summer – and the signing of Tiago – saw Parker's opportunities take a hit, and he was sold to Newcastle in July 2005.
21. Denis Zakaria
Another victim of Chelsea's sacking culture, Denis Zakaria arrived on loan from Juventus – joining Thomas Tuchel's Blues on 1 September 2022.
Only six days later, though, they were no longer Tuchel's Blues: the German was given his marching orders, and new boss Graham Potter didn't seem that keen on Zakaria – who returned to Juve having made just 11 Chelsea appearances.
20. Alexey Smertin
Alexey Smertin became captain of the Russian national team during his time as a Chelsea player, but the midfielder's time at Stamford Bridge was considerably less memorable.
Loaned out to Portsmouth upon his arrival in August 2003, Smertin enjoyed a strong first Premier League campaign – but by the time he returned to his parent club the following summer, Jose Mourinho had replaced Claudio Ranieri in the dugout.
Smertin barely featured in the Blues' 2004/05 title season (although his 16 appearances were enough for a winners medal).
19. Alvaro Morata
He's often been lampooned for costly misses, but Alvaro Morata is a far better striker than many give him credit for – although Chelsea didn't see the best of him.
Signed from Real Madrid for a then club-record £60m in the summer of 2017, the Spaniard struggled to settle in England and scored only 16 goals in 47 Premier League outings.
18. Tomas Kalas
Tomas Kalas was a Chelsea player for nine years – although he was also only a Chelsea player for four competitive games, featuring for just the seven other clubs on loan during his time as a (technical) Blue...
Incredibly, the Czech defender made more than 60 appearances for two of those clubs – Vitesse Arnhem and Chelsea's West London rivals Fulham – before eventually being sold to Bristol City in 2019.
17. Baba Rahman
Ghana left-back Baba Rahman joined Chelsea in 2015, a month after his 21st birthday – and left the club a week after turning 29, having featured just 23 times in eight years for the Blues.
All of those appearances came in his first campaign with the Blues, who loaned him out no fewer than six times (including twice to Schalke) before releasing him in the summer of 2023.
16. Robert Fleck
In 1992/93, the Premier League began – and Chelsea celebrated English football's bold new era by breaking their club transfer record to sign Robert Fleck from Norwich City for £2.1m.
It was not money well spent: the Scottish striker had been Norwich's top scorer two seasons running, but he registered a paltry three goals in 40 league appearances for the Blues – before returning to Norwich in 1995.
15. Steve Sidwell
Reading legend Steve Sidwell helped the Royals' to a superb eighth-placed Premier League finish in 2006/07, their first season in the top flight – and his midfield performances earned him a move to Chelsea.
Sidwell probably ended up wishing he'd never made the switch to Stamford Bridge, though: he was always going to be up against it trying to break into a midfield containing the likes of Frank Lampard and Michael Essien – and he left for Aston Villa 12 months and 15 Premier League appearances later.
14. Asier del Horno
An £8m arrival from Athletic Bilbao in the summer of 2005, Asier del Horno was a Premier League winner in his one and only season at Chelsea.
That hardly tells the whole story, though: the Spanish left-back couldn't establish himself in the Premier League – and received a straight red card for a foul on Lionel Messi in Chelsea's Champions League last-16 exit to Barcelona. He was sold to Valencia in July 2006.
13. Tiemoue Bakayoko
Tiemoue Bakayoko was a regular in his first campaign at Chelsea, featuring 43 times in all competitions as the Blues won the 2017/18 FA Cup – but that doesn't mean he was a hit.
The French midfielder was anything but, in fact, attracting widespread criticism for poor and clumsy displays. After four loan spells away from Stamford Bridge, he joined Lorient on a free transfer in the summer of 2023.
12. Mateja Kezman
Mateja Kezman scored a crucial goal in Chelsea's 2005 League Cup final victory over Liverpool – which brought Jose Mourinho's first trophy at the club – but that was as good as it got for the Serbian striker in his one and only Blues season.
Like so many others, prolific form in the Eredivisie – where he had banged in the goals for PSV – didn't count for too much in the Premier League, and Kezman move on to Atletico Madrid after netting just four times in 25 league outings.
11. Slavisa Jokanovic
Signed from Deportivo La Coruna in the summer of 2000, Slavisa Jokanovic failed to make his mark at Chelsea, moving on just two years later – and retiring shortly afterwards.
The midfielder would return to the Premier League in 2018 when he managed Fulham to promotion from the Championship – only to be sacked before Christmas and replaced by the man who brought him to Stamford Bridge 18 years earlier, Claudio Ranieri.
10. Juan Sebastian Veron
As one of the first Chelsea signings of the Roman Abramovich era, Juan Sebastian Veron was always going to carry a certain weight of expectation after his £15m move from Manchester United.
But that price tag ought to have served as a warning to the Blues: just two years earlier, the Argentine midfielder's £28.1m switch from Lazio to United had broken the English transfer record.
Veron's stock continued to fall at Stamford Bridge, and he made just seven Premier League appearances before being loaned out to Inter Milan.
9. Mark Bosnich
Mark Bosnich started 23 times in Manchester United's 1999/2000 Premier League title-winning campaign – but the Australian goalkeeper didn't play another game following the arrival of Fabian Barthez that summer.
So, off to Chelsea he went on a free transfer in 2001 – going on to make seven appearances in all competitions before being sacked after testing positive for cocaine.
8. Adrian Mutu
Another of the first signings after Roman Abramovich's takeover – joining from Parma for £15.8m – Adrian Mutu's Chelsea goals record was unspectacular rather than terrible, per se: the Romanian striker netted 10 times in 38 games in total.
But Mutu's Blues career ended in disgrace as, like Bosnich only a couple of years earlier, he tested positive for cocaine – resulting in a seventh-month ban from football and, ultimately, his departure from Stamford Bridge.
7. Fernando Torres
When Chelsea broke the British transfer record to sign Fernando Torres for £50m in January 2011, it looked like good business: El Nino had been banging in the goals for Liverpool – 65 in 102 Premier League games, to be precise.
But the 2010 World Cup winner didn't even manage a third of that total in 110 league outings for the Blues, peaking with eight goals during the 2012/13 campaign.
6. Chris Sutton
It's not just been in recent years that Chelsea have endured struggles with previously prolific strikers: in 1999, they paid £10m to bring 1997/98 Premier League Golden Boot winner Chris Sutton to Stamford Bridge.
But, while he had helped fire Blackburn Rovers to the 1994/95 title as one half of the famous SAS striker partnership with Alan Shearer, Sutton would be sending out an SOS to rescue him from his Chelsea misery.
All in all, he scored three goals in his one season as a Blues player – moving on to Celtic in the summer of 2000.
5. Andriy Shevchenko
Chelsea paid £30.8m to sign Ukrainian icon Andriy Shevchenko from AC Milan in 2006 – a fee which, not for the first time, saw them break the English transfer record.
Off the back of a 28-goal season for Milan, Shevchenko didn't give any impression that he was over the hill – but, for whatever reason, he just could not settle at Stamford Bridge, and he managed only nine goals in 48 Premier League games for the Blues.
4. Kalidou Koulibaly
For years, Kalidou Koulibaly was linked with a big move away from Napoli – but when Chelsea swooped to sign the Senegal captain in 2002, it was too late.
Even given the seemingly bottomless pockets of American owner Todd Boehly, paying £33m for a 31-year-old centre-back felt like a risk – and so it proved, as Koulibaly enjoyed a mistake-riddled one-season stay at Stamford Bridge.
He left for Saudi Pro League outfit Al-Hilal in the summer of 2023, with Chelsea making a £13m loss.
3. Romelu Lukaku
Unique on this list having signed for Chelsea twice, Romelu Lukaku re-joined the Blues from Inter Milan for a whopping £97.5m in August 2021 – another club-record fee.
Chelsea topped that figure with the signing of Enzo Fernandez less than 18 months later, but it was still a serious amount of money – especially when Lukaku scored just eight Premier League goals in 2019/20 (that's a touch over £12m per goal).
During that disastrous campaign, the Belgian landed himself in trouble by appearing to criticise head coach Thomas Tuchel's tactics; he returned to Inter on loan in the summer of 2022.
2. Winston Bogarde
Winston Bogarde has the dubious distinction of being possibly the most famous (or infamous) benchwarmer in Premier League history.
A 1994/95 Champions League winner with Ajax, the defender joined Chelsea in 2000. However, the signing was apparently made behind the back of then manager Gianluca Vialli – whose successor Claudio Ranieri wanted Bogarde to leave.
But, in one of the most remarkable episodes of the modern era, Bogarde opted to see out his Blues contract – reporting for training every day despite hardly ever playing, while reportedly taking home £40,000 a week!
1. Danny Drinkwater
Few careers in recent years have nosedived like that of Danny Drinkwater, whose time at Chelsea was little short of disastrous.
A £35m arrival from Leicester City – having played an integral part in the Foxes' historic 2015/16 Premier League title triumph – the midfielder's stock was at a high in the summer of 2017.
But Drinkwater would end up making just 22 appearances for the Blues – where his frustrating experience was summed up as he was sent off for kicking a 16-year-old Tottenham player in an U23 match in 2020.
Drinkwater – who, among other drama while at Chelsea, was charged with drink-driving and attacked outside a nightclub – left Stamford Bridge for good in 2022.
