5. David Luiz
Signed: 31st January 2011
Fee: £21,000,000 David Luiz is now in his third season at Stamford Bridge and his time there has certainly not been easy. Another expensive signing that has become synonymous with the Abramovich era, Luiz was expected to settle in quickly and turn from hot-head to reliable central defender. However, despite being a talented footballer, Luiz still struggles to control his emotions and is prone to outbursts on the pitch. His 13 yellow cards this season alone suggest he has not matured during his time at Chelsea and he continues to provide good odds for a sending off!