Liverpool look like securing the signing of Luis Diaz before Monday's January transfer deadline, with the Colombian being a big boost for the Reds' assault on four trophies in the second half of the season.
But given that the winger has already played in the Champions League for Porto – the Portuguese side were in the same group as Liverpool but went out at that stage – fans may be wondering whether their new signing will be eligible for the competition.
Until 2018, players who had played for one side in the competition could not play for another – this changed however, to allow teams to sign players for the tournament.
Pierre-Emerick Aubameyang was maybe the last big star to be cup-tied in Europe, after moving from Borussia Dortmund to Arsenal in the winter of 2018. Despite being bought to help Arsenal secure top four that year, the Gabonese goalscorer was unable to play for Arsene Wenger's team in the Europa League run that saw the Gunners head out of the competition against Atletico Madrid in the semi-final.
UEFA have since altered the rule, however. Now, players who have played in the group stage can move to another team and play in the Champions League for another club. There is a good example of a player like this at Liverpool, too.
Takumi Minamino, likewise, moved to Anfield in a January transfer window after playing against Jurgen Klopp's side in the Champions League group stages.
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