Steve Kean has confirmed he is hoping to make at least three more signings before the transfer window shuts.
The Rovers boss has so far signed David Goodwillie, Radosav Petrovic and youngster Myles Anderson this summer.
But the Scot is eager to boost his options up the centre of his team ahead of the deadline on August 31.
"We want to bring in another striker, we want to bring in another midfield player and we want to bring in a centre-back," he told the club's official website.
"There's no secrets in telling anybody that, those are the areas we want to strengthen.
"We've got good options in the wide areas, we've got good options elsewhere, but strengthening that spine of the team is something that we want to do and I'm confident we can do that before the window closes.
"We want to get three more in, when you include the players that have been signed - Myles, David and Petrovic - we want to have at least six additions by the time the window closes.
"We've four active bids that are sitting on the tables of other clubs, so at any point they can accept."
Blackburn were thought to be closing in on Leicester defender Sol Bamba, although their manager Sven-Goran Eriksson claims there has been no contact from the Premier League club.