On today's episode of Keys and Gray, former Blackburn manager Sam Allardayce revealed how close he came to signing Bayern goal machine Robert Lewandowski, had it not been for an 'ash cloud' which cancelled his flight to England.
Lewandowski flew to Germany instead, where he has gone on to score 333 goals in 462 appearances for Bayern Munich and Borussia Dortmund, establishing himself as one of the best strikers in world football.
'Big Sam' is not alone, here are nine transfers which fell through which undoubtedly haunt these managers to this day.
Zinedine Zidane to Blackburn Rovers, 1995
Unfortunately for Blackburn fans, Robert Lewandowski wasn't the only superstar the club squandered the chance to sign.
Rovers owner Jack Walker seemingly couldn't put a foot wrong after helping the club clinch the Premier League title in 1995, but the steel magnate's monumental mis-step came when he passed up the chance to sign France legend Zinedine Zidane from Bordeaux.
Walker was infamously quoted saying: "why would we want Zidane, when we have Tim Sherwood?"
Here's why. By the time Blackburn was relegated in 1999, Zidane had won two league titles at Juventus, the FIFA World Player of the Year and the Ballon d'Or. Meanwhile, Tim Sherwood's career fizzled out with spells at Tottenham, Portsmouth and Coventry.
Cristiano Ronaldo to Arsenal, 2003
Cristiano Ronaldo confirmed he was “very close” to joining Arsenal in 2003, before a man-of-the-match performance in a friendly against Manchester United caught Sir Alex Ferguson’s attention.
Wenger agreed a £4million fee with Sporting CP for the 18 year-old and even sent the winger a ‘Ronaldo 9’ Arsenal jersey, but Sir Alex swooped in and lured Ronaldo to Old Trafford.
Ronaldo won nine trophies in six years at United, before moving to Real Madrid for $160 million - a world record at the time, while Arsenal picked up two pieces of silverware in the decade which followed.
Rivaldo to Bolton Wanderers, 2004
Big Sam makes this list again, after coming agonisingly close to signing Brazil legend Rivaldo during his time in charge of Bolton.
The world footballer of the year even outlined his ambitions for Bolton as reported by BBC Sport, saying: "I want the challenge of trying to get Bolton into Europe for the first time in their history. It is an exciting time."
Despite the promising signs, the football gods work in mysterious ways, and in the end the deal fell through.
Diego Maradona to Sheffield United, 1978
Sheffield United boss Harry Haslam flew to South America to watch little-known 17 year-old Diego Maradona bamboozling defenders for Argentinos Juniors in 1978.
Haslam knew he was onto a winner but failed to convince the Blades board to splash $A400,000 on the prodigy.
Instead, the Blades spent a club-record $A320,000 on River Plate midfielder Alex Sabella. The move backfired as Sheffield slipped to the third-tier before offloading the Argentine to Leeds, while Diego Maradona became widely regarded as one of the greatest footballers of all time.
Steven Gerrard to Chelsea, 2004
It's hard to imagine 'Mr Liverpool' himself Steven Gerrard playing for anyone other than his beloved Reds, but the midfielder was inches away from signing for Premier League rival Chelsea in 2004.
Gerrard was reportedly set to double his $A120,000 per week wage by heading to Stamford Bridge, but the England star made a remarkable U-turn after he and his family were inundated with abusive messages from Liverpool supporters.
Stevie G stayed loyal to Liverpool by passing up the cash, plus the chance to work under Jose Mourinho, who failed to assemble his mouth-watering midfield trio of Frank Lampard, Gerrard and Claude Makelele.
Radamel Falcao to Aston Villa, 2008
Martin O'Neill reportedly had the chance to bring Colombia superstar Radamel Falcao to Aston Villa for just $A10 million in 2008.
O'Neil snubbed the offer to sign 'El Tigre' and opted for Premier League journeyman Emile Heskey instead.
The numbers don't lie - Heskey bagged nine goals in 92 league appearances for Villa, while Falcao moved to Porto where he scored 72 goals in 87 games, before signing for Atletico Madrid two years later for $A88 million.
Paul Gascgoine to Manchester United
Sir Alex Ferguson has conceded one of the biggest regrets of his decorated managerial career was failing to sign enigmatic midfielder Paul Gascgoine.
"We spoke to him the night before I went on holiday. He says 'go and enjoy yourself Mr Ferguson, I'll be signing for Manchester United," Ferguson said.
"So I went on my holidays but Martin Edwards (then chairman) rang and said 'I've got some bad news - he signed for Tottenham. They bought a house for his mother and father in the north east and that swung it".
For all of his off-field distractions, Gazza remains one of the most talented English players of all time and it's scary to think how great he could have been under the guidance of Sir Alex.
Eric Cantona to Sheffield Wednesday, 1992
For all the highs Trevor Francis achieved as a player for Sheffield Wednesday, his time as a manager produced one almighty low - the day he passed on Eric Cantona.
Cantona came from France for a trial at Sheffield Wednesday in 1992, showcasing his skills in an indoor match, but Francis was yet to be convinced they would translate to a larger pitch and asked Cantona to come back for to trial for another week on grass.
The fiery Frenchman thought he had done enough and passed on the invitation, signing for Leeds instead before heading to Old Trafford where he became club captain and a Manchester United legend.
Zlatan Ibrahimovic to Arsenal, 2000
Zlatan Ibrahimovic has never been short of self-belief, and that unwavering confidence denied Arsene Wenger the chance of signing the Swedish superstar.
He [Arsene Wenger] never actually made me a serious offer, it was more, "I want to see how good you are, what kind of player you are. Have a trial". I couldn't believe it. I was like, "No way, Zlatan doesn't do auditions"
In hindsight, perhaps Wenger should have just given him the part.