On Lucas, he is one of the best. Yaya Toure and Arturo Vidal spring to mind as being better. Luiz could work as a defensive midfielder, if he's quick enough or positionally aware enough.
I've just been reading that Ramires will be back and that Luiz will will be put back to CD !! Ho hum!!!
To be fair AC he id play some of his early games in central midfield, where he looked very promising! He very quickly got moved to central defence, where he has made me, and I guess a fair few other, Blues lose a lot of fingernails. Rafa moved him back to CM against Monterrey and he was again a class act! Unfortunately he got repositioned back again and it all went wrong!
