Sporting Lisbon sources have told Sky Sports they have rejected an initial offer from Liverpool for defender Tiago Ilori.
The Premier League side are understood to have been locked in talks with Sporting and reportedly had a delegation in Portugal over the weekend.
The Reds were willing to pay around £3million for Ilori, but Sporting are said to want a deal worth double that.
It is claimed that as part of the proposed deal Liverpool are offering Oussama Assaidi on loan, but as yet no agreement has been reached.
"The doors are open to negotiate, but for a just price," a source confirmed to Sky Sports.
"We are not disposed to sell any of our players this summer."
Sporting are currently not in the best shape financially, but it is believed they have offered Ilori a new contract.