Liverpool have recently revealed that long-serving defender Jamie Carragher will be retiring from professional football at the end of this season, meaning a rather sizable hole will appear in the Reds' back line over the summer.
That, in addition to general concerns over some of the form and quality displayed by other first-team members, means that the Reds are certain to add one new name and could perhaps even bolster their defence by more than that during the transfer window.
Picking a new defender isn't just a simple matter of seeing who makes the most clearances or tackles and throwing them into the team—they have to be able to fit into the tactics of the side, complement their defensive partner (Daniel Agger at present) and display mental and leadership values as well as technical ability.
Not to mention, the centre of the defence is unlikely to be the only area of the Reds' back four which needs some attention this summer.
With that in mind, here are five defenders that Liverpool could be looking to sign come the end of the season.