What are the Europa League squad rules?

There were additions to the B list in advance of the 20:00 BST kick-off against Real Sociedad - Radek Vitek, Tyler Fredricson, Kobbie Mainoo, Zidane Iqbal, Shola Shoretire and Zidane Iqbal, while Anthony Elanga also fits into this category.

No club may have more than 25 players on the A list and a minimum of eight spots are allocated exclusively to locally trained players, with a maximum of four of these classified as association-trained. 

A club-trained player who, between the age of 15 and 21, irrespective of nationality and age, has been registered with his current club for a period, continuous or not, of three entire seasons, according to UEFA rules. An association-trained player is somebody who, between the age of 15 and 21, has been registered with a club or other clubs affiliated to the relevant national championship for a period, continuous or not, of three entire seasons.

Clubs can register an unlimited number of players to the B list during the campaign but these must be submitted by no later than midnight CET on the day before the game in question.

Those eligible must be born on or after 1 January 2001 and, since their 15th birthday, have been eligible to play for the club for any uninterrupted period of two years or a total of three consecutive years with a maximum of one loan period to a side from the same association for a period not longer than one year.

Sixteen-year-olds can be registered if they have been at the club for the previous two years, without interruption.

When it comes to the knockout stages of the competition, clubs may register a maximum of three new eligible players for the remaining games, completed by 2 February at the latest.

These players can already have appeared in a UEFA competition this season but the maximum limit of a 25-man A list remains, while respecting the quota of locally trained players.

There are also different rules for goalkeepers - at least two must be on the A list and three in total. If a keeper is injured or ill for at least 30 days, a replacement can be registered during the season until the original player can resume his position. If the replaced keeper was registered as locally trained, the new one does not need to be locally trained.

What all this means is there is fluidity regarding youngsters in terms of the Europa League squad, as is the case with the Champions League.

With no UEFA Youth League participation this term, there may be more flexibility in this regard and it will be interesting to see if the B list changes from game to game. 

Of the sextet added for the Real Sociedad game, Iqbal and Shoretire have already made their senior debuts but Vitek, Fredricson, Mainoo and McNeill have yet to appear for the first team in a competitive fixture.

However, simply because these players are on the B list does not necessarily mean they will be named in the matchday squad, of course. We will have confirmation of this 75 minutes ahead of the 20:00 BST kick-off.