#1 Lionel Messi
Lionel Messi, like Cristiano Ronaldo, is often considered as the greatest player of his generation. Despite his unrivalled success at club level, Messi has never managed to bag any major silverware for Argentina, coming up short in the 2014 World Cup final and losing in three Copa America finals.
In the eyes of many fans, to really cement his status as the best of all time, alongside the likes of Pele and Maradona, Messi needs to win a major international trophy, and given Argentina's extremely questionable form, it seems unlikely to happen in Russia.
Messi is currently 30 years old, which means he will be 34 by the time the next tournament rolls around in Qatar. While Messi's ability has really not declined with age, it seems unlikely he will be playing for Argentina by then.
Messi briefly retired from the Argentinian team in 2016, following a Copa America final defeat and many fans feel that he will be hanging up his international shirt at the end of the upcoming tournament, whether they win it or not.