Philippe Coutinho's wife, Aine, could be the key to Yerry Mina's future at Barcelona. Arthur's arrival will mean there are too many non-EU players at the club unless Barcelona find a solution. With Paulinho and Coutinho key, that means Mina would have to be the one sacrificed for Arthur.
However, to stop the need to send Mina out on loan, Barcelona are depending on Coutinho's wife, Aine. She has double nationality, one of them Portuguese.
Portugal's law demands that for Coutinho to get a Portuguese passport, they need to be married for three years. This is fine - they were married in 2012. But Coutinho can't get his passport until January 2019. Barcelona are doing everything possible to speed up that process so Arthur can join and Mina can stay.