Cup-tied
Cup-tied is an adjective, used in association football, to describe a player who is ineligible to play in a knockout cup competition after transferring from another club during that competition.
Application
In virtually all domestic and international club cup competitions, any player who makes an appearance for a club at any stage of the competition is "tied" to that club for all future matches during that season in the same competition. This prevents a wealthy team still in the competition from gaining an unfair advantage by signing talented players from clubs that may have lost out in earlier rounds, in an attempt to increase their cup chances.
The rule applies to individual cup competitions, such that a player who plays in the English FA Cup, but not the Football League Cup, for example, is cup-tied only in the former competition. If the player signs for a new club in the same season, he is thus eligible for the Football League Cup, but not the FA Cup. UEFA club football regulations state that, with very few exceptions, players who play in a European club competition are subsequently cup-tied with respect to all European football for the remainder of the season.