It's well established that Ashley Cole isn't the world's greatest human being. While fairly mild-mannered on the pitch (standing near John Terry will make anyone look mild-mannered), he's hardly a paragon of good conduct the rest of his time, and his womanising, devil-may-care attitude does not reflect well upon him or the club, and neither does the way in which he traded his previous side for Chelsea. But for all that, he's a remarkable footballer, and one who has an impact far beyond the average left-back.
Wide defenders typically don't contest particularly important positions. Part of the reason so many attacks stem from the flanks is that they are allowed to - wide areas simply are not as valuable to an attack as the space in the centre. When one thinks of your typical full-back on the attack, at best they're going to be pinging in a few crosses to support the team's real playmakers.
Ashley Cole crosses, certainly. But he does far more than that: He switches positions depending on where the ball is. Again, this isn't exactly rare for a full-back; they all get forward, to an extent. What distinguishes Cole is the completeness with which he becomes a winger, something very few other defenders in the world could hope to pull off. Cole is possessed with the sort of touch which lets him beat players one-on-one, an eye for the pass, and the ability to put the ball into the net in the rare opportunities he gets a clear chance. He's a fine defender, too, but it's not that difficult to be solid defensively at full-back, as Aston Villa proved when they picked up and dropped spare centre half Carlos Cuellar at right-back last season, where he was nigh on impenetrable at the back but unsure on the ball and caught out repeatedly during transitions.
Chelsea take full advantage of Cole's attacking skills. Check out the Chelsea full-backs' passes (used as a proxy for positioning) for the game last week against West Bromwich Albion. First up is Paulo Ferreira, Cole's colleague on the right, and then there's the England left-back himself.
Figure 1: Paulo Ferreira's passes vs. West Bromwich Albion, 8/14/2010. By Guardian Chalkboards.
Although Ferreira played just 65 minutes against Albion at home, that's a pretty sad lack of passes by the Portuguese right back. It's obvious that the majority of Chelsea's play was coming down the other flank. So what did Cole's passing map look like?
Figure 2: Ashley Cole's passes vs. West Bromwich Albion, 8/14/2010. By Guardian Chalkboards.
Yeah, that's more like it. When Chelsea have the ball, Cole plays an absurdly advanced position, camping out in the Baggies half and acting as a spare midfield creator. This forward forays come at a cost, of course, leaving the defence exposed and having to shuffle left to compensate, but the Blues have one of the game's finest defensive midfielder corps, and they're adept at covering for their left-back's forward runs. Besides, Cole is extremely fit, and more often than not he's back in his defensive position by the time the opposition can shuttle the ball forward after a transition anyway.
It's a small price to pay for the ability to overload the midfield. Cole provides width that Chelsea so often lack, and it's his ability to compensate for not having a winger that allows the Blues to play a 4-4-2 diamond, a formation that packs the centre with midfielders and allows Drogba to shine (he can't be double-teamed by the central defenders) but does not offer much forward play on the flanks. When Chelsea play 4-3-3, the combination of Cole and his advanced teammate to drag the opposition right-back all over the pitch, creating gaps for everyone else to exploit.
Ashley Cole is so good at what he does that Chelsea have spent millions trying to replicate him on the right. Portuguese right-back Jose Bosingwa is the closest they have come, but while he performs the 'spare winger' role with aplomb, he's not quite the defender Cole is, nor is he so quick back after a transition. He's also injured, meaning that Chelsea have been forced to play defence-first Branislav Ivanovic in his spot for the better part of the year. As the wonderful Zonal Marking has pointed out, Bosingwa's injury against Aston Villa in October last year forced Chelsea to switch from the diamond to the current 4-3-3 system.
Jose Mourinho is obsessed with players who can cause an imbalance in one area of the pitch while minimising the corresponding hole that inevitably appears elsewhere. This is why he bought Didier Drogba, who routinely occupies two defenders at once unless he gets bored, and this is why he worked so hard to secure Cole's services for Chelsea. When the Special One adores a player, the rest of us mere mortals had better take notice. Ashley Cole is a huge part of the reason the Blues have been so irresistible recently, and he allows the club to play in ways that just aren't feasible with anyone else at left-back.
It's hard to separate Cole the human being from Cole the footballer, and I can't blame fans up and down the country for hating his guts, but as a player... I think I'm in love*. And not enough people are, despite him being one of England's few world class players to consistently perform at club level for his country.
*As a person I hate his guts.