A high line is a goalkeeper's contract, not a defender's

Whether a defence can hold forty yards up the pitch is decided almost entirely by what the keeper behind it is willing to do.

Every conversation about a high defensive line seems to be about the centre backs. Are they quick enough, do they step together, can they judge the moment. Fine questions. Wrong department. The line is only as high as the goalkeeper's willingness to leave his box, and that willingness is a personality trait more than a coaching point.

Think about the geometry. If you defend on the halfway line you have created forty yards of grass behind your last man that no defender can cover retrospectively, because the attacker is already running and the defender is turning. The only player who can cover it is the one facing forwards with a head start, which is the keeper, and he can only do it if he is standing near the edge of his area when the pass is played rather than on his line.

That position is genuinely uncomfortable. Every chipped ball is a potential humiliation that will be shown for a decade. Every sliced clearance outside the box is a red card conversation. A keeper who has been beaten from distance once tends to stand two yards deeper for the rest of his career, and two yards deeper collapses the whole structure, because now the defence must drop to protect him and the compression that made the press work disappears.

So when a team abandons a high line in February, I rarely believe the explanation about fatigue or about opponents figuring it out. Usually somebody got chipped in November.

The interesting part is that the skill required is not shot stopping at all. It is reading a through ball and deciding, in the third of a second before committing, between the sprint and the retreat, knowing that the half committed version is the only truly fatal choice. That skill barely shows up in the numbers a keeper is judged on. Saves per shot faced says nothing about the twelve times he came out and the ball never became a shot.

Which is why I think the sweeping keeper is still undervalued in transfer markets that are otherwise fairly efficient. Clubs pay for the spectacular save. They are actually buying, or failing to buy, the forty yards behind the defence.