The Fifa World Cup 2022 starts on 20 November – with a unique winter build-up meaning many of the world’s top stars are playing club football right up until a week before the tournament starts.
England already have their own defensive worries and a packed domestic schedule will surely mean further scares for manager Gareth Southgate, with Wales boss Rob Page also closely monitoring his squad.
But which other countries have real worries over the fitness of their key men?
BBC Sport attempts to keep track….
Dominic Calvert-Lewin: The Everton striker limped out of their 2-0 defeat to Leicester with a ‘hamstring problem’ and will undergo a scan. After the Toffees’ EFL Cup defeat by Bournemouth on Tuesday, manager Frank Lampard said he would be “very surprised” if Calvert-Lewin was fit for Saturday’s Premier League tie against the Cherries.
Reece James: The Chelsea man says he is “devastated” to miss the World Cup after suffering a knee injury against AC Milan last month. Despite being ahead of schedule in his recovery, England manager Gareth Southgate has deemed it too big a risk to take the 22-year-old.
Kyle Walker: The Manchester City defender was left with six weeks to recover his fitness after groin surgery – but says he is “confident” of making the World Cup squad.
Kalvin Phillips: The Manchester City midfielder is a major doubt after a dislocated shoulder suffered in September but City manager Pep Guardiola said Phillips is “optimistic” about being fit in time for the tournament.
Kyle Walker-Peters: The Southampton full-back is set to be out until the end of the year with a hamstring injury sustained in Saints’ 1-0 win over Bournemouth in late October.
Ben Chilwell: The Chelsea left-back has confirmed he will miss the tournament after suffering a “significant” hamstring injury in the Blues’ Champions League win over Dinamo Zagreb.
Gareth Bale: The star forward should be fit to lead Wales’ first World Cup campaign in 64 years despite appearing sparingly for Major League Soccer side Los Angeles FC. The 33-year-old says he is “not 100% fit” but is “feeling better as time goes on” after coming off the bench to score a 128th minute equaliser before LAFC beat Philadelphia Union on penalties to win the MLS Cup on 5 November
Tom Lawrence: The Dragons will be without the Rangers forward in the Gulf state after he aggravated a knee injury that has ruled him out until after the tournament.
Joe Allen: The veteran midfielder has not played for Swansea in more than a month after going down with a hamstring problem but has been named in Robert Page’s squad.
Didier Deschamps’ defending champions have arguably the largest injury list – from an admittedly frighteningly strong squad – of any country heading into the four-week event.
N’Golo Kante: The defensive midfielder will miss the World Cup following surgery to correct a hamstring problem.
Paul Pogba: The former Manchester United midfielder will also not feature at the tournament as he needs more time to recover from knee surgery for an injury sustained soon after his summer return to Juventus.
Wesley Fofana: Kante’s Chelsea team-mate limped off during the 3-0 Champions League home win over AC Milan and was not named in Didier Deschamps’ 25-man squad.
Lucas Hernandez: The Bayern Munich utility man injured his groin in a Champions League victory over Barcelona last month but is closing in on a return to fitness and was named in the squad for Qatar.
Raphael Varane: The 29-year-old left the pitch in tears during Manchester United’s 1-1 draw at Chelsea after suffering a leg injury but has been given a spot in France’s World Cup squad.
Anthony Martial: Forward Martial has recently returned to training following a back injury but missed out on a place in Qatar.
One Premier League player remains a major doubt for a Brazil side looking to lift the World Cup for the first time since 2002, but injured Richarlison is now likely to compete.
Richarlison: The Tottenham forward was seen on crutches after suffering a calf injury in Spurs’ 2-0 win over Everton on 15 October, but Tottenham boss Antonio Conte says the Brazil forward should be available for the World Cup following a scan.
Richarlison added on Twitter: “Guys, thank God it was just a big scare!! Two weeks and I’ll be back! Thank you for the messages and affection.”
Manager Fernando Santos could be deprived of the services of four important players for their Group H campaign against Ghana, South Korea and Uruguay.
Diogo Jota: The Liverpool forward will miss the World Cup after he was taken off on a stretcher with a thigh injury in added time of their 1-0 Premier League win over Manchester City on 18 October.
Pedro Neto: Wolves said the 22-year-old striker will miss the World Cup after an ankle injury sustained against West Ham on 1 October left him requiring surgery.
Pepe and Nuno Mendes: Porto expect 39-year-old Pepe to miss several games with a sprained knee, while fellow defender Mendes will be out for a few weeks with a muscle issue.
With one key striker already ruled out the Germans’ main worries centre on a Die Mannschaft stalwart with 48 caps and 15 international goals to his name and a Bayern Munich forward in good form.
Timo Werner: The 26-year-old will miss the tournament after suffering an ankle injury in RB Leipzig’s 4-0 Champions League win over Shakhtar Donetsk on 2 November.
Marco Reus: The 33-year-old Borussia Dortmund skipper damaged ankle ligaments in September. An ankle injury also kept him out of Germany’s World Cup triumph in Brazil in 2014. He returned for Dortmund in their 2-0 defeat to Union Berlin but has since suffered another setback.
Leroy Sane: The 26-year-old tore his left thigh muscle during Bayern Munich’s 5-0 win over Freiburg but returned to training in early November and is expected to be fit.
Manuel Neuer: The veteran goalkeeper suffered a shoulder injury in October but returned to action in Bayern’s Bundesliga game against Hertha Berlin on 5 November.
The Netherlands, a potential last-16 opponent for England or Wales, will also be missing an experienced international operator.
Georginio Wijnaldum: The 31-year-old former Liverpool midfielder, capped 86 times, suffered a fractured tibia in his right leg after just playing one game on loan at Roma.
Kepa Arrizabalaga: Chelsea manager Graham Potter confirmed the goalkeeper won’t play for the Blues until after the tournament after suffering a foot injury in the 4-1 defeat by Brighton in October.
The 2014 runners-up have a handful of concerns but have been boosted by the return of a key forward.
Paulo Dybala: The 28-year-old was expected to miss the competition after picking up a freak thigh injury while taking a penalty for Roma in Serie A in early October, but is now due to undergo tests and could be available.
Angel di Maria: The former Manchester United winger also suffered a thigh injury on Champions League duty for Juventus but could still make the tournament.
Giovani lo Celso: The 26-year-old Tottenham midfielder – on loan at Villarreal – has 41 caps for his country but looks set to miss the tournament after coming off in a 1-0 defeat to Athletic Bilbao with a muscle injury on 30 October.
The US, Group B opponents of England and Wales, have key injuries at either end of the pitch.
Chris Richards: The Crystal Palace defender will miss out with an ongoing leg injury that has sidelined him since August. He tweeted: “Gutted that this injury has ruled me out of the World Cup but I know that the boys will go crazy regardless … will be rooting for y’all the whole way.”
Daryl Dike: The West Bromwich Albion striker has been out with a thigh issue since August and was not selected in the squad for Qatar, despite recently returning to training.
Miles Robinson: An Achilles tendon tear has ruled out the Atlanta United centre-back.
Sadio Mane: The Bayern Munich striker left the field after 20 minutes of their 6-1 win over Werder Bremen on 8 November, 13 days before his country’s first game against the Netherlands.
Boss Gerardo Martino has huge concerns over two of his top stars, but says he will give both until the very last minute to prove their fitness.
Raul Jimenez: The Wolves forward has not played since 31 August due to a groin injury and faces a race against the clock to be fit.
Jesus Corona: Winger Corona broke his leg in August and despite recovering ahead of schedule, Sevilla coach Jorge Sampaoli said he will not be fit in time to play for Mexico at the World Cup.
Son Heung-min: The Tottenham forward is confident of playing some part in the finals after undergoing successful surgery on a fracture around his left eye. He had to be replaced after he suffered a blow to the head in his side’s final Champions League group match against Marseille on 1 November. Spurs boss Antonio Conte, said: “Now, he is at home. I am confident, confident that he can come back quickly and play the World Cup for South Korea.”
Marcelo Brozovic: The Inter Milan midfielder has not played in almost a month after coming off with a thigh injury during Croatia’s Nations League win over Austria in September but is on the brink of a return to action.
Ronald Araujo: Barcelona stated in September the defender would likely miss the tournament due to surgery on a torn thigh muscle but the 23-year-old has been included in Uruguay’s preliminary World Cup squad.
Jakub Moder: The Brighton midfielder will not feature for the Poles in Qatar after rupturing his anterior cruciate ligament in April.
Atiba Hutchinson: The Canada captain, 39, has not played at all this term for his club side, Turkish outfit Besiktas, after suffering a bone bruise in pre-season but is expected to be fit in time to play in Qatar.
Alphonso Davies: The Bayern Munich full-back, 22, will miss his club’s next two games with a hamstring injury but his World Cup participation is “not in danger”.
Imran Louza: Watford midfielder Louza, 23, will miss the tournament after breaking his leg against Millwall in mid-October.
Yuta Nakayama: The Huddersfield Town defender will miss the World Cup after being ruled out for the rest of the season with an Achilles injury.