The overlap that scares a defence comes from a centre back

Wide runs stop being predictable the moment the runner is somebody nobody has been trained to track.

The run that genuinely unsettles a back four does not come from the full back. It comes from behind him. A centre back arrives on the outside, forty yards from anywhere anyone has seen him before, and for two seconds a professional defence has no rehearsed answer at all.

Speed has nothing to do with it. Defending is a picture built out of habits, and those habits are organised by shirt. A winger tracking a full back is doing a thing he has done ten thousand times, and he does it half asleep. The holding midfielder will not drop out into that channel, because in his head the channel belongs to somebody else. So the decision falls to whichever player is least sure it is his to make, and it gets made late. That delay, not the run, is what creates the cross.

The standard objection is the counter, and the objection is priced badly. Sides who do this keep the other centre back and a holder at home, which is the same rest defence they would have kept with an overlapping full back anyway. What actually hurts them is duller than a counterattack. It is the throw-in taken quickly while the centre back is still jogging back, and it is the corner conceded thirty seconds later with the shape not yet reset. Coach those two moments and most of the risk goes away.

The real reason almost nobody does it is not tactical at all. Centre backs are selected, coached and praised for never being there. Ask one to make that run and the first fifty attempts are bad, mistimed, too early, taking the space the winger wanted. Managers do not have fifty attempts worth of patience for something that looks like a blunder while it is being learned.

There is also a shelf life, and pretending otherwise is how a good idea gets ruined. It works because it is unfamiliar. Once it is on video the opposition assigns a man to it in the meeting, and by the third time you use it against the same side you are simply playing with outfielders in odd positions for no reward. Use it in bursts. Save it for the afternoon when the low block will not move for anything.

Most teams will never try it, because a centre back that far upfield looks like a mistake right up until the ball goes in.