Ronald Koeman has claimed that Barcelona cannot hope to be the best team in the world without Lionel Messi and bemoaned his side's lack of financial freedom to sign players this transfer window.
Barca find themselves in crushing debt leading to Messi's exit on a free transfer to Paris Saint-Germain, who have had perhaps their best-ever window, signing a number of top players, while both Manchester clubs have splashed the cash as well.
Koeman admitted that his side will struggle this season to compete with the spending power of these clubs, but asked for patience as his younger players continue to develop and grow.
"I understand what people who love this club can feel, but the economic situation is what it is," Koeman said via SPORT. "It's frustrating, but you have to be realistic. Economically we can't compete with Paris, City or United. That's right and we have to accept it.
"We aspire to the maximum and we must have a winning mentality, but we cannot hope to be the best in the world. We have lost the best player in the world and I insist that we have to be realistic. We cannot demand the usual because the team is different.
"We are building a team with an exciting future, but you have to be patient. Pedri won't be the same at 24, as he is at 18. Or Nico [Gonzalez] or the others. We are building something, but we need time."
Koeman added that he has been frustrated by certain player's decisions to stay put at Camp Nou, leaving him with a bigger squad and wages the club can't afford right now.
"The club know what I want and who I want to keep working with," he added. "I have always said I respect the players with contracts, but everyone knows perfectly well who we count on in this squad and who will have a hard time playing games.
"For some players, it's very complicated and it's not good for them or for us. If we have all our players back, we are going to have 31, 32 players. It's impossible to work with that many. How can a coach manage 32 players?"
Samuel Umtiti is set to stay at Barca despite the club trying to move him on, but Koeman confirmed Miralem Pjanic and Ilaix Moriba could both leave before Tuesday's deadline.