Alex has played 135 games for Chelsea after being signed by Jose Mourinho
QPR have agreed a fee with west London rivals Chelsea for Brazilian defender Alex, BBC Sport understands.
The 29-year-old centre-half was the subject of a bid from an unnamed Premier League club – thought to be QPR – earlier this week.
Chelsea rejected the offer but are keen to recoup a fee for a player who has been told he has no future at the club after handing in a transfer request.
Alex is expected to begin talks with QPR next week.
But he has also been linked with a return to his homeland or a move to France.
Alex was signed by Chelsea from PSV in 2004 but had to be loaned back to the Dutch side because of work permit issues and only moved to England in 2007.
Meanwhile, the Blues are closing in a deal to replace Alex with Bolton defender Gary Cahill, BBC Sport understands.
It is believed the England centre-back has already agreed personal terms and is in London on Saturday to have a medical.