I thought I would put up this thread about squad rules as there are often posts questioning the rules re squad size requirements. Note these rules are from Uefa re CL or EU participation, la liga re liga participation and a third re Copa and Spanish super cup participation.

Background - there was an article in AS a couple of days ago that clearly spelled out these requirement.

Non EU players. This one applies to CL and la liga - club can only have 3 non EU players.
Right now they have 5 in squad, Valverde, Militao, Vinicius, Rodrygo, Kubo.  Lunin and Jovic are also non EU, but are considered community players under an EU rule, where they are considered legal EU eligible for work in EU.

Club is now expecting Valverde’s Spanish passport before beginning of September. Club’s plan is to use the opened slot for Rodrygo although they may still register him for Castilla, as they did with Vinicius last season, if the squad size limit of 25 has Issues. If the passport doesn’t come thru, they will register him with Castilla and would be able to put him on B list for CL play. There is a lower ligas rule that only allows one foreign player per team which means both Kubo and Rodrygo can’t be registered with Castilla. So depending on what happens with Rodrygo, Kubo may have to be registered with JuventileA. Kubo will have to wait a year and given the age and time in Spain, none of Miltao, Vinicius nor Rodrygo will be freeing up a spot for Kubo anytime soon!

Spanish Players - this is a liga rule. Club has to have 8 spanish trained players, 4 of which have to have been with club.

Currently they are just meeting this requirement. The 4 Real Madrid trained are Carvajal, Nacho, Valverde and Lucas, plus the others meeting the spanish trained requirement (4) are Ramos, Isco, Brahim, Odriozola, Asensio (if he is included in 25 man squad) and Mariano (if he remains). Now you see the dilemma with selling Lucas, Nacho, Isco, Asensio or Odriozola!!!! These numbers are part of the decision process now that they have deleted the spanish content down to lowest number in Years!

exception to EU rule - this one from Copa and Spanish Supercup - Vinicius, Rodrygo, Kubo are considered amateurs (less than 2 years pro experience and can be eligble to play in these competitions.

Squad size of 25

Currently there are 27 players in squad (excluding Kubo) with a possible 2 more to come (De Beek, Pogba). That means at least 4 players have to go.

The most likely are James, Bale, Mariano, Lunin (loan).

The remaining 22 are:
Courtois, Navas,
Carvajal, Odriozola, Varane, Militao, Ramos, Nacho, Marcelo, Mendy,
Modric, Casemiro, Kroos, Valverde,
Isco, Benzema, Hazard, Vinicius, Rodrygo, Brahim, Jovic, Lucas, Asensio ( note - Asensio may be excluded from list (injured) until at least January)