Finding Inverted Full Backs With Data

Investigating one of football’s most popular tactical trends through a numerical lens.

You probably know what an inverted full back is by now. With Pep Guardiola finding new ways to innovate and dominate, while Twitter analysts post lineup graphics with inward-pointing arrows and boxes around the half-spaces, the term has engrained itself into mainstream football vocabulary.

I am not here to provide any tactical insight or propose a new development, rather, I will simply be trying to show how event data can be used to quantify inversion. If you are interested in pursuing more of the tactical side of things, I will leave you a couple good starting points.

First, this nice graphic from Eric Laurie:

Then, this video from Tifo Football:

Now, let us get into the numbers.

Passing in central areas

The first thing that comes to mind when I think of inverted full backs is the general fact that they operate in central areas. These players drift inside, away from the touchline, and combine in the half-spaces or the central channel.

With that in mind, the first method I used to look for the top inverters was finding the share of a full back’s passes played from a central position. Essentially, I split the pitch into four quarters going left to right, and any passes played from the two inside quarters were classed as central.

These are the results:

Right off the bat, this looks pretty good. The poster boy for the inverted full back role, João Cancelo, has the highest Central Passing Rate by a good margin. His teammates in that Guardiola system, Kyle Walker and Oleksandr Zinchenko, also sit in the top four.

Elsewhere, Danilo takes the silver medal, with Alex Sandro doubling the Juventus presence in fifth. Stuart Dallas of Marcelo Bielsa’s Leeds United makes an appearance, and, perhaps unsurprisingly, Niklas Süle’s time at right back for Bayern Munich saw him tucking in centrally.

Visualizing the passing locations of some of these top players against a full back who is far more glued to the touchline shows the magnitude of the positioning difference.

The likes of Cancelo and Danilo played an abundance of passes from the centre, while, especially high in the attacking third, they did not operate out wide as much. For someone like Trippier, on the other hand, it is clear they are more focused on getting to the endline and maintaining their side’s width themselves.

Watching this in action, you can see the inverted full backs stepping into positions that are very much centre midfielder-like. This gives them new passing angles and options that are not traditionally associated with the full back position.

João Cancelo, playing as an inverted right back, steps centrally and slides in a through ball.

Danilo makes an inward run from left back, picking up the ball inside the centre circle and sending it out to the wing.

Thus, you can start to see why players with strong vision and distribution, or a history of playing in midfield, rank highly in terms of Central Passing Rate.

Playing the ball to wider teammates

That first metric seemed to yield pretty good results, but I wanted to see if something even more granular could provide any additional insight. Basically, if a full back inverts, that should mean there is another player on their flank closer to the touchline, maintaining the side’s spacing and width.

How can this be measured without tracking data? What I have tried to do is quantify the frequency at which a full back completes passes to a teammate who is a significant distance wider than him. So, if they are on the left side of the pitch, a pass that moves the ball towards the left touchline, and if they are on the right, a pass that moves the ball towards the right touchline.

From there, we can find a full back’s Outward Distribution Rate — the percentage of their total completions that fit this criteria. Here is the top of the leaderboard:

There are a lot of familiar names from the first metric, but with a bit of reshuffling. Kyle Walker tops the list here, and Cádiz’s Iza Carcelén, perhaps an under-the-radar inverter, makes another appearance, this time up in sixth. Carcelén, Anaitz Arbilla, and Nacho Vidal show that their could be a bit of a trend here among bottom-half La Liga sides.

Interestingly, two Bologna defenders pop up in the top five here. From what I watched of them this season, their manager, Siniša Mihajlović, is definitely open to tactical tweaks and player rotations. Takehiro Tomiyasu and Lorenzo De Silvestri, who both played mostly on the right, had outward passing rates almost twice those of Bologna’s main left backs.

This throws another tactical wrinkle into the mix on a team level. There can be sides like Manchester City, who utilize two highly inverted full backs, while other sides rely on one full back to invert, while his counterpart on the opposite flank plays a much more traditional role.

Either way, the differences between a high-volume and a low-volume outward distributor — like Everton’s Lucas Digne — are very clear.

Keep in mind that those are all of Digne’s outward completions from 1,000+ total completions.

Of course, when you have full backs playing towards the sideline like this, it means their role in build up and progression differs from the traditional duties of the position.

Kyle Walker tucks in to receive the ball before spraying it out to his winger, Ferran Torres, on the touchline.

With Bologna trying to break down the opposition, Takehiro Tomiyasu positions himself in the right half-space and distributes to his right winger, who provides the width.

An inverted Oleksandr Zinchenko picks up the ball in a very central position and sends it out to the left wing.

This concept of measuring a full back’s invertedness by how often they have a teammate wider than them could definitely be improved upon with tracking data. You could use things like each player’s positioning relative to each other or team shape throughout the whole match, instead of just looking at passes.

However, outward distribution still seems to a do a good job identifying full backs who tuck in and then distribute, as opposed to playing vertical down the flank or from outside-in.

Defending in central areas

When you hear inverted full back, the first thought that comes to mind is certainly inversion in possession. Something I was interested in, though, was if there are also full backs who tuck in at a high rate on the defensive side.

For this, I used the same methodology as the Central Passing Rate, but with all of a player’s defensive actions — tackles, challenges missed, passes blocked, and interceptions — instead of passes.

Implementing that methodology, here are the full backs with the highest Central Defending Rates:

There are a few recurring names from the offensive metrics with De Silvestri, Carcelén, and Dallas, but a lot of shake up in general. Perhaps the main takeaway here is that teams can utilize full backs who tuck in heavily in possession, but stay wider out of possession.

João Cancelo is probably the best example of this, with a Central Defending Rate of just 18.57 putting him far below the top names here. On the other hand, someone like Stuart Dallas seems to remain pretty inverted on both sides of the ball.

Looking at these rankings and some of the guys just outside the top ten — like Luke Shaw in 12th — a big factor here seems to be physical profile. For lack of a better way to describe this, a lot of these top names seem to be right around the 6 feet/183 cm mark, and have a bit of stockiness or oomph about them.

What I am really getting at here is that I guess it makes sense to have a Rubén Duarte or a Benjamin Pavard closer to goal, and thus more central, when you are defending, because they will be much more effective at dealing with things like crosses or physically strong off-ball runners.

While aerial duels do not go into the Central Defending Score, if you check the Football Reference scouting reports for a lot of these guys, they are above the 80th percentile for aerials won by full backs. West Brom’s Darnell Furlong, for instance, is in the 99th percentile over the last calendar year.

Thus, while in possession, you probably want full backs who are more technical and have better vision to invert, defensively, it seems that shifts more towards physical strength and aerial ability. These players tuck in more to deal with things like crosses and runners, but it then leads to them making their tackles and interceptions in more central areas.

That being said, you can still have someone like Stuart Dallas, who is not very strong in the air, inverting frequently, which could say more about the uniqueness of that Leeds United system.

Now, for the difference between a high-volume central defender and a low-volume central defender, you can have a look at Duarte and Pavard against Juventus’ Juan Cuadrado.

Someone like Duarte is more likely to come inside and win the ball off of a centre forward or around zone fourteen as opposed to just stepping towards the sideline when the opposition winger receives the ball.

Rubén Duarte stays inside and steps to Luis Suárez, while the Alavés winger tracks the wide runner.

A recovering Stuart Dallas pressures the ball centrally and blocks a pass, while the other three members of the Leeds United back four have shifted to the left to cover him.

Benjamin Pavard anticipates a pass into the half-space and steps inside to cut it off.

Once again, this methodology could almost certainly be improved upon with tracking data. Even access to just StatsBomb’s pressure data would be a big help, as that would give you a larger sample size and help limit the variance involved compared to just using “traditional” defensive actions.

Scouting for inverted full backs

Finally, I figured I would dive into what could be the most useful application of these metrics — scouting inverted full backs from more obscure leagues. I have collected the same data for the most recent completed seasons in a bit of a random assortment of competitions — Turkish Süper Lig, Portuguese Primeira Liga, Russian Premier League, and Argentine Primera División — and these are some of the full backs who stood out:

Milton Casco (River Plate)

Playing for Marcelo Gallardo at River Plate, 33-year-old Milton Casco was one of the top inverted full backs in possession. Here is how he stacked up in the three metrics, along with his percentile ranks compared to other qualifying full backs in those four leagues:

• Central Passing Rate: 22.53 (100th percentile)
• Outward Distribution Rate: 10.27 (94.1st percentile)
• Central Defending Rate: 18.18 (33.1st percentile)

Braian Cufré (Vélez Sarsfield, now at Mallorca)

Braian Cufré inverted heavily on offense and defense for Vélez Sarsfield under Gabriel Heinze. He earned a move to Mallorca for the 2020/21 season, in which he helped them win promotion back to La Liga. Still only 24, the Argentine should have his prime years left ahead of him. His stats were:

• Central Passing Rate: 22.48 (99.3rd percentile)
• Outward Distribution Rate: 13.88 (100th percentile)
• Central Defending Rate: 27.72 (90.1st percentile)

Maksim Nenakhov (Akhmat Grozny)

In the Russian Premier League, youngster Maksim Nenakhov seems to be one of the top examples of an inverted full back. Aged 21, Nenakhov ranked highly across the board.

• Central Passing Rate: 17.74 (93rd percentile)
• Outward Distribution Rate: 7.22 (78.1st percentile)
• Central Defending Rate: 25.49 (84.6th percentile)

Fabricio Bustos (Independiente)

Independiente’s Fabricio Bustos was once a very hot prospect in the footballing world, even receiving two caps for the Argentine national team in 2018. While he has not moved out of his home nation yet, Bustos is still heading into his prime at 25, and he shows the ability to invert in possession.

• Central Passing Rate: 17.53 (92.4th percentile)
• Outward Distribution Rate: 7.91 (86.1st percentile)
• Central Defending Rate: 21.57 (57th percentile)

Douglas Santos (Zenit)

Part of the Brazilian contingent at Zenit, 27-year-old Douglas Santos is another player with strong inverted full back tendencies on the offensive side. In his left back role, he has won back-to-back league titles. Here is how he compares to the sample metric-wise:

• Central Passing Rate: 16.52 (88th percentile)
• Outward Distribution Rate: 10.05 (93.4th percentile)
• Central Defending Rate: 23.08 (68th percentile)

Kalindi (Nacional)

In the Portuguese Primeira Liga, Kalindi, a right back for Nacional, is an interesting case. He has high rates of tucking in centrally both in and out of possession, yet the 27-year-old rarely distributes the ball out to the wing, giving him this blend of stats:

• Central Passing Rate: 16.95 (89.9th percentile)
• Outward Distribution Rate: 4.46 (24.8th percentile)
• Central Defending Rate: 24.21 (76.6th percentile)

Gökhan Gönül (Fenerbahçe)

Lastly, we will finish where we started; with an aging veteran. This time, we have a full back from the Turkish Süper Lig — Fenerbahçe’s Gökhan Gönül. At 36, Gönül is still playing a big role for one of Turkey’s top sides, and he puts up pretty high inversion numbers in each area.

• Central Passing Rate: 15.34 (79.8th percentile)
• Outward Distribution Rate: 6.99 (75.1st percentile)
• Central Defending Rate: 25.62 (85.2nd percentile)

So, those are some examples of how you can apply these metrics to players you may have never even watched before to find out which full backs invert most often or which teams utilize the tactic.

I would like to add that if you cast your mind back to those initial big five European league rankings, there were multiple examples of two players from the same side being close to one another. This is a reminder that actually being an inverted full back depends a lot on the system a player is in and what their manager asks them to do.

This begs the question: Are great inverted full backs really found, or are they made? Right now, I would lean towards saying they are made. Thus, it might be more beneficial, at the moment, for a big club to look for a centre midfielder or a full back playing a traditional role, who has the right traits to be molded into an inverted role (see the work done by Guardiola or Bielsa).

Over time, though, as more and more sides start to follow the trend — like, in that sample of leagues I used, Argentine teams were definitely inverting a lot more, while Portuguese and Turkish sides, not so much — it will probably become more beneficial to say, “This guy plays well in an inverted full back role for his current side, so he should slide into our system well.”

That will be all from me, though. If you have access to some more advanced data or can build off of my work here in any way, I strongly encourage you to experiment and improve upon what I have made.