Rotation happens where it is cheapest, not where it is needed

Managers rest the players whose absence is easiest to explain, which is why the spine of a squad never gets a break.

Look at a heavily rotated team sheet in a busy December and count the changes by position. Wingers, full backs, the front man, a midfielder. Now look at the goalkeeper, the two centre backs and the holding player. Same names. Almost always the same names.

Rotation is real, and it is applied to the parts of the team where a mistake is survivable.

The logic is not stupid, exactly. Positions with high defensive consequence have the worst cost of error, and a coach who rests a centre back and then concedes twice from a misunderstanding at the back will face a different sort of press conference than one who rests a winger and draws nil-nil. So rotation drifts towards the roles where the replacement is closest in quality and where a poor performance shows up as an absence of good things rather than a visible catastrophe.

The trouble is that this is close to the opposite of what the physical data would suggest. Wide players and forwards do the sprinting, yes, but centre backs accumulate a specific and underappreciated load, the repeated maximal decelerations and jumps and collisions, and they do it for ninety minutes every three days for ten months with no interruption whatsoever. Goalkeepers absorb repeated impacts with the ground and almost never sit out. The players who never rotate are not resting because their position looks quiet on a distance chart.

There is a squad-building consequence too. If the spine never rotates, the club has no reason to buy a genuine second choice for those roles, so it buys a cheaper one, so the gap widens, so rotation becomes even less appealing. The pattern reinforces itself over several transfer windows until the club has four excellent wingers and one fit centre back.

I would rather see clubs plan rotation from the physical profile and then solve the political problem, which means recruiting a second centre back good enough that using him is not an apology, and telling the supporters in September what the plan for the winter is rather than defending each individual selection on the night.

That takes a manager with time and a board willing to spend on a player who will start twenty games.

Neither is common. So the same centre back plays every match until his body files an objection.