With Neymar turning down a move to Stamford Bridge after a ~£25M offer by the Blues, Chelsea have a significant amount of money earmarked for transfers that they haven't used. The young Brazilian has made the entirely reasonable decision to stay home a little while longer, but Chelsea's apparently serious pursuit of the Santos star indicates that they were probably expecting him to join the club, leaving a gap in the squad where they were expecting to slot him in.
Will the team look to sign Neymar-lite, someone who can happily play winger-cum-striker a la Salomon Kalou? Will they look elsewhere to find a spot to upgrade? Will they save the cash for the next transfer window? Our new #7, Ramires, is the only major acquisition the Blues have made this summer, and he was brought in to shore up an area where Chelsea had major issues last season. Now, with the departure of Ricardo Carvalho and the forced retirement of young Sam Hutchinson, there's a rather alarming hole in our defensive depth. If one of John Terry, Alex, or Branislav Ivanovic goes down to an injury, things start to look decidedly worrisome in the centre of the defence.
The problem? The £33M price tag, significantly above what Chelsea were willing to shell out on Neymar. While I suspect that Luiz would be comfortably more valuable to the team over the next couple of seasons than his younger compatriot, as a central defender he simply does not have Neymar's star potential, making spending that much money on him a riskier proposition from the PR perspective. I've been fortunate enough to watch Luiz play a few times, and he's been extremely impressive, but I'm not convinced that the Blues should be shelling out £33M on him, and it's not even my money.
I would expect Chelsea to be spending money on a defender, but the transfer market so inflated whenever the is connected to anyone, I wouldn't expect it to be anyone there's been much buzz about.