Does ‘Potterball’ exist?: Searching for patterns to how Chelsea’s manager plays

In the 32nd minute at the Red Bull Arena, Chelsea’s possession game caught fire.

On the right of defence, Trevoh Chalobah played a short pass to Christian Pulisic. Retreating under pressure, the American laid it off to Jorginho, who directed it towards the halfway line. There it found Raheem Sterling.

Drawing a Red Bull Salzburg player with him into the Chelsea half, Sterling laid the ball off to Mateo Kovacic, who whipped a pass to the left where Kai Havertz was in a sea of space.

The Germany international advanced into the final third and drew the final Salzburg defender, Bernardo, before squaring it to Pierre-Emerick Aubameyang.

Rather than dink the ball over the onrushing Philipp Kohn, Aubameyang lashed a low shot into the goalkeeper’s body. The best passing move of Graham Potter’s tenure fizzled out without the ending it deserved.

Yet for 14 seconds and 12 touches, Chelsea carved open Salzburg, propelling the ball precisely from one penalty area to the other. It felt like a statement of stylistic intent.

But was it Potterball? The Athletic found out.

Formations

During a joint interview before Brentford’s 0-0 draw with Chelsea, Thomas Frank, coach of the home side, was encouraged to ask Potter a question of his choice. He picked a serious one, delivered with a smile: “Why do you keep changing formations all the time?”

“We don’t really see the formation as the end goal,” Potter replied. “We see how the team is playing. The team needs to look consistent regardless of the formation, and then it’s about the personnel — how you want to attack the opponent, how you want to defend the opponent. Those things we consider. Hopefully, there are things that look the same even though the formation changes.”

Chelsea supporters already know that trying to decipher Potter’s set-up from the graphic tweeted by the club before a match is difficult. It isn’t much easier once play starts, with the formation looking vastly different depending on the phase of play and which team has possession.

That is how Potter likes it. He wants his players to be comfortable switching roles and structures, often within matches, able to think for themselves within the team concept. He is understood to have been pleased with how seamlessly Chelsea’s players have absorbed his instructions, a process made simpler by their recent experiences playing for Thomas Tuchel — another coach who prizes tactical flexibility.

That emphasis was evident when Potter coached Swedish side Ostersund, transforming them over seven years from a fourth-tier provincial minnow into a European football success story. Initially, he favoured a 4-4-2 shape with one of two strikers frequently dropping deeper to create a 4-2-3-1. Against more conservative opponents that often morphed into a 4-2-4, with both wingers pushing higher up and the full-backs making supporting runs from behind.

Towards the end of his time in Sweden, however, Potter was showing even greater variation in his formations, with three-at-the-back systems often favoured to counteract superior opponents such as Galatasaray and Arsenal in the Europa League.

In the short video below for The Coaches’ Voice, Potter gives a detailed explanation of his tactical setup for Ostersund’s 2-0 home win over Galatasaray, arguably his most famous victory.

The video hints at why Potter has valued three-at-the-back systems at Brighton and Chelsea: the structural difficulties for opponents attempting to press a three-man defence, the easy transition into a five-man defensive block when required, the ability to stretch opponents across the width and length of the pitch, and the control of the “half-spaces” between the flanks and the middle of the pitch at both ends.

In his single season at Swansea City in 2018-19, Potter’s primary shape was 4-2-3-1. Two deep-lying central midfielders allowed the full-backs to be more adventurous, but Kyle Naughton often drifted infield as an inverted full-back on the left, enabling his team to build and advance possession up the middle.

Three years at Brighton gave Potter the chance to showcase the full range of his tactical dexterity. They lined up as a 4-4-2, 4-2-3-1, 3-4-3 and 3-5-2, and while the latter two were the most common starting formations, Potter could regularly be seen telling his players to shift from a back three to a back four from the touchline. That was made easier by Dan Burn and later Marc Cucurella being comfortable as wide centre-backs or full-backs.

Within those systems were bespoke tactics, devised to counter specific opponents. Sometimes the two wing-backs were instructed to join the first line of pressing, creating a de facto front four out of possession. With the ball, one of the two strikers might drift out to a flank to create overload possibilities or enable a wing-back to run infield — something seen between Havertz and Sterling on Chelsea’s left side against Salzburg.

Fluidity has always been Potter’s primary objective, but what stylistic elements does he look for?

Principles of play

It is hard to imagine Potter pontificating in a press conference about his “philosophy” or “idea of football”. He laid out his vision in plainer terms when he arrived at Chelsea last month.

“I want a tactically flexible, possession-based team,” he said. “Players who are brave, who aren’t afraid to make mistakes, who can get on the ball and show courage and really try to enjoy their football.”

It’s likely that the mere mention of Potterball would prompt an eye-roll from Potter, but that doesn’t mean there aren’t characteristics he consistently looks to implement beyond their tactical arrangement on the pitch.

Sadly for our purposes, public advanced data is scant for Potter’s time at Ostersund. However, the stylistic details can be seen in the numbers from his time at Swansea, and Brighton in particular, where he had three seasons to evolve the team in the direction he wanted.

In the 2018-19 campaign in south Wales, Potter’s team finished 10th in the Championship while registering the fifth-highest expected goals (xG) in the division according to data from StatsBomb via FBref. The pizza graphic below shows they did it by favouring slow, patient possession football — they ranked last in direct speed (in metres per second) and long pass share per 90 minutes. They were in the bottom half for direct attacks, which are possessions that start in a team’s defensive half and result in a shot or touch inside the opposition box within 15 seconds.

The graphic also indicates how Potter values possession when it comes to defence. His teams like to defend with the ball and generally prefer to recycle it when they win it back rather than launching a quick counter, lowering the risk of another turnover. Swansea’s possession dominance had a significant role in them conceding the fifth-fewest shots per 90 minutes in the division in 2018-19.

Pressing, however, was not a significant part of Potter’s game plan at Swansea; they allowed an average of 13.5 passes per defensive action (PPDA) — a proxy of pressing intensity — in 2018-19, ranking them 21st among Championship sides. Partly as a result, their field tilt — a metric that shows territorial dominance by measuring the share of possession only in the respective attacking thirds — was also middling.

Pressing became a far more prominent element of Potter’s approach the following season at Brighton; as you can see below, they ranked seventh in the Premier League for PPDA.

That didn’t immediately translate into defensive solidity, but by the 2020-21 season, Potter had successfully transformed Brighton into one of the most difficult teams to attack in the Premier League. Their pressing remained fiercely effective, and though their possession share dipped a little, slowing the ball served to marginally increase their number of shots taken per 90 while massively decreasing the number of shots given up.

Last season, Brighton had the statistical profile of an elite Premier League team under Potter, tightening their control of matches through patient possession, pressing even more effectively, and ranking well in shots taken and shots given up per 90 minutes.

The numbers support the notion that Potter was swiftly transforming Brighton into a team strikingly similar to Tuchel’s Chelsea on a fraction of the budget — an achievement not lost on Todd Boehly and Clearlake Capital.

It is still too early in Potter’s reign at Chelsea for the numbers to paint a reliable picture of his impact, but he was appointed to build upon Tuchel’s work rather than rip it up and go in a different direction.

The early data suggests it is working as intended: after six Premier League games under Tuchel and five under Potter, Chelsea rank second in the division for tackles in the attacking third, third for touches in the attacking third, and fifth for shots conceded per 90 minutes, according to StatsBomb data via FBref.

The future

In some ways, that thrilling sequence against Salzburg was atypical of the style that has come to be associated with Potter: fast, incisive vertical passes through the lines rather than slow, patient possession to cement control and minimise the risk of dangerous opposition attacks.

But it might also indicate one way that Potter’s style will evolve at Chelsea. He has never coached a squad this talented before, capable of dominating the majority of opponents and winning matches in a variety of ways.

One problem Tuchel never solved at Chelsea was how to consistently generate clear scoring chances against deep-lying opponents focused on frustrating his team. There were specific tactical reasons for that in certain games, but at times it appeared as though his high press was almost too effective, pinning opposition teams back in their low defensive blocks rather than giving them a chance to expose themselves.

The way Salzburg were lulled into a trap in the 32nd minute and cut through was reminiscent of the brand of football that elevated Maurizio Sarri to international renown at Napoli, and which forms part of the style of Potter’s successor at Brighton, Roberto De Zerbi.

It’s too soon to say exactly what form Potterball will assume at Stamford Bridge, but it’s clear he has arrived with all the tactical tools he needs.

(Top photos: Getty Images; design: Sam Richardson)