Here are everything you need to know about what the cup-tied rule is, which competitions it applies to and previous examples
Almost every domestic cup competition worldwide implements a "cup-tied" rule, which has had a significant influence in the transfer market in past seasons.
The rule no longer applies to European competition but is still implemented in the likes of the FA Cup and Carabao Cup – and here's what you need to know about it.
Being cup-tied means that a player isn't allowed to play for two different teams in the same domestic cup competition in the same season.
For example, if a player moves from one club to another during the January transfer window, they will be unable to participate with their new club in a domestic competition that they had already been involved in with their previous team.
It does not apply for league competitions that involve a table, just cups with knockout rounds.
Cup-tied rules only apply for domestic club cup competitions such as the FA Cup and Carabao Cup.
If a player appears for a club at any round of the competition, they are tied to that club for future rounds of that tournament. Should a player appear in an FA Cup first round tie and move to another club in January, they will be forbidden to feature in further FA Cup fixtures for their new side.
This rule was initially implemented to dissuade affluent clubs from buying players during the January transfer window to strengthen their side and give them an unfair advantage over smaller teams in the competition.
Conversely, a player being cup-tied might decrease their value should they wish to move to another club in January.
Being cup-tied only applies to single competitions. If a player is cup-tied in the FA Cup, they will still be able to feature in the League Cup and vice-versa.
UEFA used to apply cup-tied rules Champions League and Europa League but abolished them ahead of the 2018-19 season.
That year marked the first time a player would be eligible to play for two different clubs in the group stage and the knockout phases of both competitions in a single season.
Previously, they used to be allowed to switch teams had they been playing in different competition – such as if they left a side playing in Europa League for a side competing in the Champions League in January – but were forbidden to compete in the same tournament with their new side.
Being cup-tied made life difficult for Philippe Coutinho and Barcelona after he arrived from Liverpool in 2018. Coutinho had already featured in the Champions League with Liverpool during the group stage, making him ineligible to play in the competition with Barcelona.
Arsenal ran into similar trouble when they signed Pierre-Emerick Aubameyang from Borussia Dortmund that same season.
Aubameyang had featured for Dortmund in the Champions League, and was to sign for Arsenal, who were competing in the Europa League. But as Dortmund finished their group in third place, they dropped down to the Europa League, making him ineligible for the Gunners.
As previously mentioned, if both clubs are in the same European competition, an arriving player is forbidden to play for the second club in the same tournament.
The cup-tied rule drew criticism from figures in the football industry, their argument mainly focusing on high-profile players – iterating that clubs may buy players not to succeed in cup tournaments but to strengthen their side in league competitions.
UEFA said about abolishing the "cup-tied" rule: "This is in line with the existing regulatory situation in the different domestic leagues, which does not impose restrictions on the eligibility for competitions of players registered for a new club during the winter transfer window."