Inverting a fullback quietly costs you a crosser you cannot replace

Moving a fullback into midfield fixes your rest defence and empties the one area that used to feed the box.

The argument for inverting a fullback is genuinely good, which is why almost everybody does it now. You step him inside, you get a third body next to the pivot, your build-up survives a press with an extra passing angle, and when you lose the ball you already have three men standing in the middle of the pitch instead of two men and a hopeful sprint back from the touchline.

That last part is the real prize. Rest defence. Losing the ball is not the problem, losing it with your fullbacks eighty yards upfield is the problem, and inverting solves it without asking anybody to defend more.

Now the bill. You have removed a specialist. A fullback who has spent fifteen years learning to deliver an early ball from a standing start on the run is not interchangeable with a winger who arrives at the same patch of grass off a different angle. Crossing is a craft, and it is a craft that lives at the point where the touchline meets the eighteen yard line, which is exactly the spot you have just vacated.

Watch what happens to the box. A team with two inverted fullbacks fills the middle of the pitch and empties the wide areas, so the winger holds width alone, gets doubled, and the only service into the six yard box comes from a cutback that requires beating a man first. Against a low block that is a bad deal. You have optimised for the phase where you lose the ball, in a game where you have seventy percent of it and lose it rarely.

I think this is why you see so many sides invert one fullback and not two. The asymmetry is not indecision. It is a team saying we will pay for rest defence on one side and keep a crosser on the other, usually the side with the better delivery and the more static winger.

There is a version of this that annoys me, though, which is the fullback who inverts because it is fashionable and has neither the passing range to be useful in midfield nor the licence to overlap. He stands in a half-space, receives sideways, plays sideways, and is praised for positional discipline.

Positional discipline that produces nothing is just standing in the right place while losing.