Barcelona sporting director Andoni Zubizarreta says more signings could be made this month.
Barca have just completed a deal for former Arsenal captain Thomas Vermaelen.
The Belgium international joins Luis Suarez, Ivan Rakitic, Claudio Bravo, Marc-Andre ter Stegen and Jeremy Mathieu as newcomers at Barca, who will be under the guidance of new coach Luis Enrique next season as they look to recover from a hugely disappointing campaign under Gerardo Martino.
He said: "With the addition of Thomas we completed a defensive line of a very high level. There are options that we are working on for the exit of some player, as such we're not discarding that others could come in.
"What I can say is that at midnight on August 31 we hope to have the best squad possible. Even though we are very happy with the players that we have, if there is a chance to improve it, we will try.
"Until the first or second (of September), when we talk about the market being closed, anything could happen."
For the big stories and the banter follow us on Twitter: @tribalfootball