The Blaugrana, who were confirmed as champions of Spain on Saturday, are hoping to bring in a replacement for goalkeeper Victor Valdes, a center back and a striker.
Real Madrid's 1-1 draw with Espanyol on Saturday night handed the Blaugrana their fourth title in five seasons, but the Catalans' humiliating 7-0 aggregate defeat by Bayern Munich in the semifinals of the Champions League has left the lasting impression upon the club's hierarchy for the need to strengthen during the offseason.
"Victor Valdes has told us that he will not continue, so we need to try to find a replacement goalkeeper this summer," Bartomeu told SPORT. "But also a central defender and a forward."
The Blaugrana chief also insisted that Barca does not need to be completely rebuilt, arguing that had the club been in better physical condition, it would have beaten Bayern.
"If it had not been for that [their alleged end-of-season fatigue], we would have played in the Champions League final," Bartomeu said.
Therefore, Bartomeu believes that there is no need for doom and gloom and that the club's fans should enjoy their Liga title-winning parade.
"It is a celebration that the team deserves, especially [coach Tito] Vilanova and [defender Eric] Abidal, but also all of the people who have been following Barca," Bartomeu said. "We must be grateful to these players. The first half of the season was spectacular. Things are still going well, so we have much to celebrate."
Vilanova and Abidal have both battled back from cancer to play their part in this season's title triumph.