With Messi expected to move to Paris Saint-Germain, Koeman must prepare for life without the four-time Champions League winner.
Memphis Depay and Antoine Griezmann will have incredibly large shoes to fill in the 2021-22 campaign, while Barca players past and present used social media to praise their former team-mate.
Gerard Pique, who won the treble with Messi in his first season back at the Catalan club, posted on Instagram that nothing will ever be the same again following the end of an era.
Now you are leaving, but I know that one day you will come back, the centre-back continued. There are pending things to do. Have fun, enjoy wherever you go and keep winning as only you know how to do. Here we will miss you. I love you Leo.
Luis Suarez, formerly part of the formidable trio with Messi and Neymar, pipped Barca to the title with Atletico Madrid last term but he too revealed his admiration for the best player ever .
I will always be grateful for how you received me since I arrived because of what a great human being you are, Suarez wrote.
Proud to have shared thousands of wonderful moments at [Barcelona] and to be lucky to have played with you. I sincerely hope that what happens in the future is the best for you and your family. I love you so much.
