The Blues have been linked with Lucio for most of the summer, but Bayer seemed to have held firm to hang onto one of their prized assets.
However, talks seem to have progressed between Chelsea and Bayer - which has led to the German side beginning their search for a replacement.
The Bundesliga giants dispatched agent Wolfgang Kuhlmann to South America this week, to see if a deal could be brokered for the highly rated Alex - who had been linked with Real Madrid.
"Bayer Leverkusen want Alex to occupy the vacancy left by Lucio," Kuhlmann confirmed to the Brazilian press.
"He [Lucio] is being negotiated to Chelsea of England."
Any deal for Lucio is likely to go through as soon as possible, which means January - when the transfer window reopens.
Chelsea are very well equipped in defence, but with Roman Abramovich at the helm - no deal involving The Blues can be dismissed.
Bayer have lined up a $6 million move for Alex, and they seemingly would not be doing that unless they needed to replace Lucio.
Real could very well have their say and should they make their interest official, then they would be the favourites to land Alex.
