Matheus Cunha is expected to leave for Manchester United, while talks over a new deal with Nelson Semedo have stalled.
"As soon as possible we'll have a clear picture of the squad and we can start our work," Pereira said on Friday.
"If we lose players with quality, we must replace them, because next season we want to be better than this season.
"It's time to understand the players we need to balance the squad and to look forward at players. Usually they propose some players, me and my staff check them, and in the end we decide.
"It's not about money because I don't know business, but about the quality of the players."
Agents want to send their players to us
Laying out the type of player he wants the club to sign, Pereira admits he wants to see "hunger" in any new arrival.
He explained: "It's important to bring players that want to come, that want to live in Wolverhampton and play in the best league in the world.
"Family players, with character and personality to work in a simple but beautiful city. This competition is the best in the world and we must go for players that really, really want to come here, like me.
"A lot of players are trying to come because they want to work in the Premier League. Players that worked with me, agents have started to send a lot of players and it means they want to come.
"We need players with hunger to play here, to achieve something special. Everything you do in this league has a huge impact, world impact."