Chelsea's formation relies on the double pivot and at the moment we have Mikal, Lampard and Ramiras for that role with only ramiras excelling and only Romeu for cover.
I think Lucas (the liverpool player) would be excelent for the role. He was a full Brazilian international before his injury and is likely to get his place back. He is always voted liverpool's player of the season and is very modest and would combine well with Oscar.
Also watching the being liverpool show he looks like he is very underpaid (drives a BMW and lives in a tiny house) so would jump at the chance to join chelsea and would be a cheap transfer.
Come on Roman buy him!