Defence
Laurent Koscielny (France) - Centre-back
Laurent Koscielny was expected to be France's first-choice centre-back alongside Samuel Umtiti in Russia. He would have provided the experience and composure at the back to a team bubbling with attacking talent.
The Frenchman, who was hoping to retire at the end of a successful World Cup campaign will, unfortunately, see an early end to his international dreams. The Arsenal skipper was enduring a disappointing campaign at the club level and his season was sadly ended in the second leg of the UEFA Europa League semi-final against Atletico Madrid.
The 32-year old suffered a serious Achilles tendon tear that will keep him out for six months. The Arsenal man fell to the turf visibly devastated and his career might now be in the doldrums as it will be a long way back from an extremely threatening injury.
Matija Nastastic (Serbia) - Centre-back
When Matija Nastasic began his Manchester City career in 2012-13, he quickly established himself as a fan-favourite and he also seemed to be destined to reach great heights. However, his career hasn't quite blossomed in the way he would have expected. After he was frozen out at the Etihad, the Serbian moved to Schalke in search of more playing time.
But, his time at Schalke hasn't been too kind on him either as he has suffered a spate of injuries that has seen him go in and out of the team. Despite this, he has remained a regular starter while donning his national colours and was expected to be the key man in the centre of the Serbian defence.
The Serbian defence, which includes Branislav Ivanovic and Alexander Kolarov, two men on the wrong side of their 30s, needed a youthful but experienced head in the middle. But Nastasic sadly suffered a serious long-term knee injury in a Bundesliga clash in early April.
The initial diagnosis said that he would be ruled out for three months. But sadly, he hasn't won the battle and the injury will see him miss out on the World Cup this summer.
Dani Alves (Brazil) - Right-back
Daniel Alves is one of the most decorated footballers on the planet, having picked up a massive haul of trophies with Sevilla, Barcelona, Juventus and Paris Saint-Germain, and he would have loved to cap off a memorable career with a World Cup winners medal.
Dani Alves, who still remains one of the best right-backs in the world, was expected to start in the same position for Brazil and provide them with the width and energy from the right-side of the pitch.
His passing and crossing from the right make him an exciting attacking option when required, just like his counterpart on the left side - Marcelo. However, life doesn't always provide fairytale endings and sadly that is the case with Alves too.
The marauding right-back picked up a knee injury during the Coupe de France final and will spend the summer recovering from the injury, rather than leading his side to World Cup glory. The 35-year old's place in the XI is likely to be taken by Manchester City's Danilo.
Joe Gomez (England) - Left-back
Joe Gomez was signed by Liverpool in 2015 and immediately broke into Brendan Rodgers' squad before sustaining a long-term ACL injury. The young defender returned this season and he took advantage of preferred right-back Nathaniel Clyne's injury absence by cementing his place in the eleven, despite heavy competition from Trent Alexander-Arnold.
The versatile English defender has the ability to play across the back-line. Though he's predominantly played at right-back this season, experts feel his best position lies in the centre of the defence.
Gomez made his debut for England in a Man-of-the-match display against Brazil in an international friendly shut down Neymar on the wing. A strong and clever player, the 21-year-old was in contention for a place in England's World Cup squad before a devastating long-term ankle injury ruled him out of the tournament.