On Tuesday evening, Barcelona confirmed to Associated Press that Messi had submitted a formal document to the club indicating his desire to leave, with specific reference to a clause in his contract that allows him to depart on a free transfer.
The club has stressed that this clause expired at the end of May, and that their desire remains for Messi to end his career in Barcelona, but the Argentina forward's heart appears to be set on moving, particularly following a discussion with Koeman.
Messi's notice comes just days after he and the Dutchman held crunch talks over his future and the situation at the club, and it has now been reported that their discussion contributed towards his decision to leave the club.
Koeman has been wielding his sword since replacing Quique Setien as the club's new manager and, according to Spanish publication AS, who cited Diaro Ole, his frank words during the meeting convinced the record six-time Ballon d'Or winner that now is the right time to leave the club.
"Your privileges in the squad are over, you have to do everything for the team. I'm going to be inflexible, you have to think about the team," Koeman is reported to have said during the conversation.
Messi made his senior debut for Barca at the age of 17, and has spent his entire professional career with the Catalan giants, scoring an incredible 634 goals in 731 appearances and winning no fewer than 34 major honours with the club.
Fans of Barcelona lined the streets on Tuesday evening following the news of Messi's desire to leave in a protest against the club's board, and called for the resignation of president Josep Maria Bartomeu.