Andre Villas-Boas says Chelsea and QPR have yet to agree a price for Alex.
The central defender has been given permission to speak to QPR regarding a move to Loftus Road, with new manager Mark Hughes keen on adding him to his defence.
A move for Nedum Onuoha is also in the pipeline but Hughes and QPR need to sort out the Alex situation first.
The Brazilian is discussing terms with QPR but Villas-Boas claims Chelsea have yet to receive a bid they deem acceptable.
"Alex has been authorised to have talks with QPR but there is no agreement between the clubs," the Chelsea manager said.
"We are speaking about a Brazil international of great value. He had a transfer request accepted but it's always difficult to sell a player of this dimension for a price we don't see fair."