Christopher Samba is set to complete a £12.5m move to QPR from Russian side Anzhi Makhachkala after agreeing personal terms and passing a medical.
It is understood the ex-Blackburn defender, 28, will receive £100,000-a-week, including bonuses and add-ons.
The centre-back used his own Twitter account on Thursday to state that he was in London.
QPR manager Harry Redknapp is also pressing ahead with plans to sign Stoke striker Peter Crouch.
Anzhi head coach Guus Hiddink admitted he was disappointed to lose Samba.
"It's not a very good situation," Hiddink told Russian newspaper Sport Express.
"Samba was with us during this season, began preparations for the winter training camps and suddenly this opportunity arose with an English club. Yesterday [Tuesday] he left for England. Unfortunately, we didn't even have a chance to say goodbye to him. Everything has developed very quickly."
Samba left England in February 2012 when Anzhi agreed to pay Blackburn £12m, amid interest from Tottenham, Redknapp's former club.
With Ryan Nelsen set to leave Loftus Road to manage Toronto FC, and Anton Ferdinand moving to Turkish club Bursaspor on loan, QPR have been desperate to sign an authoritative central defender with Premier League experience.