Raph Koster uses an analogy with sports to make a point about structure in multi-player games. He chose the wrong sport though.

First some terminology. Most of the recent online games require you to choose a class (a healer, a warrior, a wizard or whatever) and you are then constrained to learn only those skills that that class is allowed to learn. When you form a group to battle the dragon, you have to choose a balanced mix of classes – a healer to heal, a warrior to fight, a wizard to cast spells – because, clearly, there is no way that a warrior might know some magic or that wizards might learn some first aid. This gives the games, to me, an artificial feel. It takes away opportunities to improvise.

A lot of sports are like that – American football, baseball, cricket, rugby – they have rules about who can throw the ball, who can wear extra padding, who can stand in front of the back foot of the scrum. As a result, the people who excel at those sports start to look a little freaky. All the locks are 8ft 3in tall, all the linemen are 400lbs, all the batters look like they are on steroids.

Soccer is not like that. There are only two classes. The goalkeeper and everyone else. The goalkeeper is a special case (and freaky) but everyone else has the same skills – they all tackle, they all pass, they all score goals, they all cross the ball. They just have different blends of the same set of skills.

Look at Henry. You probably wouldn’t even pick him out as a sportsman. He just looks like an ordinary chap but he is one of the best players in the world. Look at Ashley Cole & Gabriel Heinze. Both defenders by trade but both able to slot in to the attack as well as any world-class winger. Players in the same role often have wildly different skills sets – Rossi, Rooney, Crouch, Adriano, Drogba and Shevchenko are all strikers.
Go to any random city in the world and find a group of 12 players to play some soccer and they will all be able to play in any position. Some will be better goal scorers, some will naturally choose to defend. Sure, they’ll argue over who is going to go in goal because goalkeeping is a different animal altogether. It’s the exception that proves the rule.

Soccer is skill-based. That’s just one more reason why soccer is the beautiful game.