Need to know
The first Man Utd players will enter the World Cup today with three nations represented by Old Trafford stars.
Matheus Cunha
Matheus Cunha's Brazil will enter the World Cup today
All you need to know about Manchester United players at the World Cup...
Manchester United have 13 players still registered at the club appearing at the World Cup this summer and the first of them enter the tournament on Saturday.
That 13 includes Casemiro, who will officially become a free agent during the tournament, with his contract expiring at the end of June.
But it doesn't include Ederson, who is yet to officially sign for the club. United have agreed a £35million fee with Atalanta and agreed terms for the 26-year-old.
Ederson will have a medical and sign the paperwork once the tournament is over. United fans could get a glimpse of their new signing when Brazil face Morocco on Saturday night.
That game could pit Matheus Cunha against Noussair Mazraoui. Cunha has a battle to keep his place, with Igor Thiago and Endrick competition up front and Vinicius Jr and Raphinha first choice on the wings.
There is also a growing campaign to get Neymar in the team. He won't be fit to face Morocco but he could be targeting Cunha's place, so the United man will want to make a good impression against Mazraoui.
After Brazil vs Morocco, it is the turn of Scotland to enter the tournament. They face Haiti and 19-year-old United midfielder Tyler Fletcher will be hoping to get some game time off the bench.
Fletcher was a surprise name in Steve Clarke's squad, having played just 17 minutes for United, but he could be a first-team option for Michael Carrick next season.
Altay Bayindir and Amad will enter the tournament tomorrow, with Turkey and Ivory Coast playing their first group games.
Later in the week it will be the turn of Senne Lammens, Manuel Ugarte, Lisandro Martinez, Diogo Dalot, Bruno Fernandes, Kobbie Mainoo and Marcus Rashford to begin their campaigns.