The Blaugrana were knocked out of the Champions League last-16 on Wednesday with PSG winning the tie 5-2 on aggregate.
Reports have started to suggest that Messi, whose contract at Barcelona expires at the end of the season has made his last European appearances for the Catalan club.
As reported by Goal, while speaking after the game, Koeman spoke about Messi and expressed what he thinks about his current situation as he said, "Leo's seen for a while that the team is improving with the changes we've made. [There are] many youngsters with quality and a big future coming in, so it's not a question of having doubts about this team."
While Messi remains the heartbeat of FC Barcelona, there is no question that the Catalan giants have seen the future with the youngsters they have in their side for the past year. These youngsters have now started to gain relevant exposure and have been featuring in big games.
Players like Ronald Araujo, Sergino Dest, Riqui Puig, Pedri, Francisco Trincao, Oscar Mingueza, Ilaix Moriba and Ansu Fati have all made their mark, with each of those players 22 or younger.