Five England players withdrew from the squad with injuries on Monday before the forthcoming Nations League matches, with Declan Rice, Cole Palmer, Marcus Rashford, Kobbie Mainoo and Tino Livramento all dropping out.
There is no formal process for withdrawing from an international squad outside a major tournament.
BBC Sport understands the Football Association allows players to withdraw from England squads following a conversation between the medical departments of the player’s club and that of their national side. Medical assessments are also often carried out by both parties.
It is believed that other football associations use a similar process, with no standardised practices in place.
However, there is a strict process in place at major tournaments such as the World Cup or European Championships.
In order to withdraw through injury from a final tournament squad, some level of medical proof of injury would be required and must be approved before a player can withdraw.
There is also no formal process for adding players to the squad after the initial selection has been announced.
There is a more formal process at major tournaments, often before the start of that team’s opening match for outfield players. Goalkeepers have fewer restrictions as this is a specialised position.
Uefa has no restrictions or regulations in place when it comes to players withdrawing from national squads outside the finals of a major tournament, with any necessary protocols being at the discretion of each nation’s respective football association.
For the Nations League, all Uefa requires is that nations submit a 23-player matchday squad before 23:59 Central European Time the day prior to the match.
That squad must consist of at least three goalkeepers.
For the Nations League finals, teams are required to submit squads that consist of 26 players.
This article is the latest from BBC Sport’s Ask Me Anything team.