The 29-year-old Brazilian centre-back has had a transfer request accepted by the club, but manager Andre Villas-Boas only seems willing to sell the player if the price is right.
Chelsea, however, have denied the reports. "I can say at this time there is no agreement between the clubs," said a spokesperson for the club.
Villas-Boas added: "I'm sure that the clubs can reach an agreement if they continue to push.
"We know Alex's market value and we're just not going to let him go quite easily, not that QPR's offer is far, far off.
"He is a player that has attracted a lot of interest from Premier League clubs and from abroad."
Alex has made 133 appearances for Chelsea since joining the club in 2007.