"We have the names and the players, but sometimes there are clubs who speculate over possible signings by Barca to manipulate the price," Bartomeu said at a news conference analysing the Catalan club's situation.
"All I can say is that they are names that have been agreed with (new coach) Luis Enrique and they excite us," he added.
"For example, (sporting director Andoni) Zubizarreta already has the names of the centre backs although they are not signed yet as there are clubs who think their value will go up after the World Cup."
Barca hired Luis Enrique, a former player with the club, to replace Gerardo Martino, who stepped down after a disappointing debut season in 2013-14.
The team often looked toothless in attack, despite the presence of Lionel Messi and Neymar, and the defence was shambolic at times, conceding far too often from set pieces.
Barca have been linked with a move for Liverpool's Uruguay forward Luis Suarez, despite his ban for biting at the World Cup, while centre back Jeremy Mathieu is said to be pushing to join from La Liga rivals Valencia.
Bartomeu said some players would have to leave to make way for new arrivals but left open whether midfielder Xavi, who at 34 is coming to the end of a glittering career, would play on for another campaign.
"He has won the right to decide what he thinks is right and we will help him however he wants," Bartomeu said.
"If it was another player we would be the ones saying what he had to do but seeing as it's Xavi we are giving him time.
"The day he leaves he will pass into history as the most successful player we have ever had."
Barca had received enquiries from "many clubs" about the possible availability of Chile forward Alexis Sanchez but they were "counting on him" for next season, Bartomeu said.