Barcelona chief Andoni Zubizarreta has welcomed the arrival of Sao Paulo fullback Douglas.
Zubizarreta cannot rule out further adding to the squad in the coming days.
"We needed an extra full-back, another option to increase competition. We have two full-backs with different styles," Zubizarreta said.
"We're working to make the best team possible so that on September 2 we can say that we have a team which we are happy with. A lot has been happening during the past few hours. The market is still very active. Tomorrow we will unveil Douglas; we'll meet Villarreal at the weekend and see what else we can do. A lot of transfer deals are concluded here in Monaco..."
