A strong, powerful centre-half is worth his weight in gold.
So much money is spend on defensive recruits who end up failing miserably. It's a vital yet often elusive piece in a successful side's jigsaw.
You can have the finest attacking talents in the world, but if you've got a joker in your backline, all their very best efforts are undermined.
The Premier League is renowned for many things, but resolute defences isn't one of them. Some suggest that the art of defending has been lost altogether in the name of 'entertainment'.
Nevertheless, four central defenders have emerged of late as fine exponents of the spoiler's craft. Each has quickly become a cult hero amongst their own fans, whilst gaining mainstream admiration.
But which one of Chris Smalling, Mamadou Sakho, Gabriel Paulista or Nicolas Otamendi would you rather have in your defence? Who would you trust with your life/slender one-nil lead?
Now we know many will argue: 'Why have you included X?' or 'What about Y?' - but this isn't a question of who is the best defender in the league - otherwise we'd include John O'Shea.
We've picked these four names because, for one reason or another, they have come into their own this season. They are all revered by the fans of their respective clubs, and we want to know if you agree.
There's a poll at the bottom of the page, but we're after your opinions. So reply on Twitter/Facebook and we'll include the best comments in a follow-up piece...
Nicolas Otamendi (Man City)
Age: 27
The rugged Argentine has assimilated incredibly quickly to English football. He was renowned for his one-on-one defending in Spain, as well as his no-nonsense style. They have both endeared him to the Etihad faithful.
Gabriel Paulista (Arsenal)
Age: 24
He may be scrawny to look at, but Gabriel is as strong as an ox and as tough as they come. In many ways he is very 'un-Arsenal' type defender, in that he takes far greater pleasure in destroying attacks than starting them.
Mamadou Sakho (Liverpool)
Age: 25
Many doubted the strong Parisian when he first joined Liverpool (including yours truly), but they have been silenced by his recent form. His fine use of the ball has been the biggest revelation, but he has also emerged as a leader.
Chris Smalling (Man United)
Age: 25
Smalling was seen as a joke figure for a long time, but the laughter has subsided. Under Louis van Gaal he has quietly emerged as one of the finest defenders in the land, coming out of his meek shell and taking charge.
