Chelsea captain John Terry has undoubtedly been one of the most consistent centre-backs in the Premier League over the last 10 years.
Chelsea's 'captain, leader, legend' has proved the doubters wrong by putting in a number of imperious displays for the west London side this season.
The 32-year-old has been reinstated into Chelsea's starting line-up by Jose Mourinho.
Terry was often left on the sidelines by Rafa Benitez as the Spaniard instead opted to play David Luiz alongside Gary Cahill in the heart of Chelsea's back four.
Chelsea's Terry has been plagued with injuries over the last couple of seasons - with his knees seeming to cause the defender a lot of trouble.
Terry is no longer able to play three games a week and David Luiz does not seem to be the world-class defender that the west London club will need when the former Nottingham Forest loanee retires.
Branislav Ivanovic is often deployed at centre-back when Terry is unfit, but Mourinho said at the start of the season that he saw the Serbian international as a right-back rather than a central defender.
With that in mind, Mourinho must sign a world-class stopper that will be able to replicate the same level of performances that Terry used to put in week-in, week-out.
Chelsea have been linked with making a £30million move for Eliaquim Mangala - but I believe Mourinho should switch his attention to Borussia Dortmund's Mats Hummels.
The 24-year-old Germany international has been in superb form for Borussia Dortmund over the last couple of seasons - building an outstanding partnership with Neven Subotic.
Hummels has been linked with the likes of Manchester United and Barcelona but has so far rejected overtures from Europe's top clubs to stay at Dortmund.
However Dortmund would surely find it hard to reject a £30million-plus bid for their star defender.
Dortmund manager Jürgen Klopp will be reluctant to let Hummels go - especially as he could lose Robert Lewandowski and Marco Reus next summer - but money talks and Chelsea certainly have a lot of it.