Benfica and Celtic in the Europa League: squad registration rules

The fixture and the framework

Google search activity in Portugal links Benfica and Celtic with the Europa League. People are searching for the match itself and for daily news about Benfica. The fixture involves two clubs that usually expect to play in Europe's top competition. For a transfers section, the interesting part is the system that decides who can actually take part.

Every club in a UEFA competition must submit a squad list. Only players on that list can play. Domestic registration with the Portuguese or Scottish league does not count for this. A player can be signed, paid and eligible at home and still be unable to play in a European tie, because UEFA keeps its own register under its own rules.

That register has two parts. List A is the main squad and has a capped number of places. List B is for younger players who have come through the club, and it can make the squad larger without using up List A places.

Origins of the rules

The current system took shape as UEFA tried to answer two questions at once. How should clubs be able to use foreign players under European free-movement law? And how could competitions still reward clubs that develop their own players? Explicit nationality quotas could not survive the legal changes that followed the Bosman ruling. UEFA's answer was the "locally trained" player. The test is where a player was developed, not which passport they hold.

Benfica and Celtic both played in European football long before any of this. Their meetings belong to an era when squads were mostly local by default, and both clubs count European Cup history as part of who they are. Today's version of the fixture runs under a far more regulated system, in a competition that has changed its name and format several times.

The Europa League itself replaced the UEFA Cup. More recently UEFA dropped the group stage and moved to a single league phase. This was part of a wider overhaul of all three of its club competitions.

How it works today

List A. A club can register up to 25 players. Eight of those places are reserved for locally trained players. A locally trained player is either club-trained, meaning developed at the club itself, or association-trained, meaning developed at another club in the same national association. No more than four of the eight can be association-trained. If a club does not have enough qualifying players, it does not fill the spare places with others. The list simply gets shorter. That is why academy output can be worth more to a club than its transfer value suggests.

List B. Younger players who have been eligible to play for the club for a set continuous period can go on List B. There is no cap on the number of List B players. This lets clubs give academy players European experience without taking a List A place.

Deadlines. Lists must be submitted before the league phase begins. Transfer business that finishes after the deadline does not automatically give a new signing the right to play in Europe. A club can make a domestic signing who has to wait for the next registration window to play in UEFA matches.

Knockout window. After the league phase, clubs still in the competition can register a limited number of new players for the knockout rounds. The exact limits are set in that season's regulations. This is why mid-season signings sometimes play in domestic matches before they play in European ones.

The league phase format. Each club plays eight different opponents, four at home and four away. All 36 clubs sit in one table. The top eight go straight to the round of 16. Clubs placed from ninth to 24th play a knockout play-off, and the bottom 12 are eliminated. A club's position affects which route it takes and how many more matches it plays. Squad depth matters because those matches are added to the domestic schedule.

Results of this particular meeting are not known here, and this article makes no prediction about them. What is at stake structurally is clear. Each result moves a club's place in the single table, contributes to UEFA coefficients that affect seeding and national allocations, and earns performance-related prize money. That money then flows into each club's transfer budget.

Common misconceptions

"Signed means eligible." It does not. Domestic registration and UEFA registration are separate processes. A signing completed after the UEFA deadline can be eligible at home and ineligible in Europe.

"Locally trained means national team eligible." The test looks at where a player was trained between certain ages, not at nationality. A foreign player who joined an academy young can qualify. A home-grown international who developed abroad may not.

"The squad cap limits how many players a club can use." List A is capped but List B is not. Clubs that develop players well can use more of them in total than the List A limit suggests.

"The Europa League is a smaller version of the Champions League." The league phase formats are similar. The prize money, coefficient points and qualification routes are different, and those differences affect how clubs plan their squads and their spending.

"Clubs in the competition can't sign players mid-season." They can. Players registered in the knockout window can take part from that point. The window is limited, not closed.

Where to look next

The main reference is UEFA's published regulations for the Europa League each season. They set out list sizes, the locally trained definitions, deadlines and the knockout registration rules. UEFA also publishes its club coefficient rankings and its distribution of revenue between competitions. Those documents explain the financial side of each result.

For the domestic side, look at the competition rules of the Portuguese league and the Scottish Professional Football League, and at FIFA's regulations on the status and transfer of players. Club annual reports, where they are published, often break out European income separately. That shows how much each club's squad planning depends on it.

Frequently asked questions

Who can play for a club in the Europa League?

Only players a club has registered with UEFA on its squad list for the competition. Domestic registration is not enough. The list has two parts. List A holds up to 25 players, with places reserved for locally trained players. List B covers younger players who have been at the club continuously for a set period. A player missing from both lists cannot take part, whatever their status in domestic football.

What does locally trained mean in UEFA competitions?

A locally trained player was registered with a club in the same national association for a set period during their youth, whatever their nationality. There are two kinds. Club-trained players developed at the club itself. Association-trained players developed at another club in the same country. UEFA reserves eight of the 25 List A places for these players, and no more than four of the eight can be association-trained.

Can a Europa League club sign new players during the season?

Yes, but only within limits. Once the league phase is over, clubs still in the competition can register a limited number of new players for the knockout rounds. That season's UEFA regulations set the exact number and conditions. A signing completed outside those windows can still play in domestic matches but cannot play in Europe until the club can register them.

How does the Europa League league phase work?

Thirty-six clubs go into a single table. Each plays eight different opponents, four at home and four away. The top eight go straight to the round of 16. Clubs placed ninth to 24th play a two-legged knockout play-off for the remaining places, and the bottom 12 are eliminated. The format replaced the old group stage as part of UEFA's wider overhaul of club competitions.

Why do Europa League results matter for transfers?

Every result earns prize money and adds to UEFA coefficient points. The prize money goes into club budgets that pay for transfers and wages. Coefficient points affect a club's seeding and their country's access to future European competitions. For clubs that regularly sell players and reinvest, steady European income makes squad planning more predictable. Weak results can reduce what a club can spend in later windows.

Sources and further reading

• UEFA: Europa League regulations covering squad lists, locally trained player rules and registration deadlines
• UEFA: club coefficient rankings and revenue distribution documents for its club competitions
• FIFA: Regulations on the Status and Transfer of Players, the framework for registration and transfer windows
• Google search trends for Portugal: the signal linking Benfica, Celtic and the Europa League