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Data Analysis: Scouting the market for left-backs

As has been well documented, within the past decade, we have seen the common full-back role change, both stylistically and in importance to a side. During this period, there has been a sharp twist in focus upon the offensive abilities of the full-back, with less emphasis laid upon their defensive duties. In the market, it is believed that there is a severe lack of elite-quality available to be found at left-back in particular. Simultaneously, there are a host of top European clubs who are scouting the market for a first-choice left-back, notably Chelsea, Manchester United, and others.

Benjamin Chilwell has been the topic of much discussion regarding his future at Leicester City. His rise from Leicester’s academy to the first-team has been one of great interest to many clubs, with Arsenal especially keen on his services back in 2016, before he had even made a Premier League appearance for the East Midlands club.

At 23 years old, he produced three goals and three assists to help his side finish 5th in the Premier League, and while these figures are not sensational, his best work is to be found in his ball progression, as will be discussed later. Despite this, his work has come under some criticism from some fans, who claim that his performances have been overrated by the general media.

This data analysis will help us to highlight, through the use of data and statistics, whether or not there is an elite pool of talent for clubs at the very top to delve into. Our dataset consists of players who have played primarily as a left-back, played at least 1000 minutes in the league (in Europe’s top five leagues, plus Liga NOS, Jupiler Pro League, Eredivisie, and Russian Premier League), between the ages of 18 and 26, as there is extensive research suggesting a player peaks at the age of 27.

This data analysis could be used by elite clubs, competing in the Champions League, to discover which left-backs would make for a smart acquisition as a first-choice player in their starting XI. At the end of the analysis, we will highlight the five players who could join a top side, and provide some good value to their side immediately, and have room to improve. Plus, one surprise candidate who might not be at that level but has played at an elite level this term.

Ball Progression

Modern full-backs are often key towards ball progression for their side. Whilst some systems encourage their full- backs to move in-field to join the midfield, other systems operate to exploit the width of the pitch and attack down the wings.

The first section of this data analysis displays our sample across two metrics which assess their ability to make progressions down the field either with a pass or a run.

Progressive runs are a good indicator of whether a full-back can carry the ball into more advanced areas, whilst progressive passes demonstrate the player´s ability to advance the team closer to the opponent’s goal.

Data Analysis: Scouting the LB market - key recruitment for elite clubs - statistics

Englishman Max Clark leads the way for progressive passes with 12.88 per 90. He also has an above-average value of 1.97 progressive runs per 90. Going from Hull City to Holland, the 24-year-old has enjoyed a successful second season at Vitesse Arnhem, helping them settle at 7th position in the table.

Leading the way for progressive runs is previously mentioned Benjamin Chilwell, with 3.69 per 90. He has now been first-choice left-back at Leicester City for a few seasons, and we have seen him develop his game tremendously in that time. He also produces 9.65 progressive passes per 90, which ranks as above average.

A player who ranks particularly high in both statistics is Andrew Robertson. The 26-year-old Scotsman combines 12.71 progressive passes and 3.02 progressive runs per 90. Alongside his excellent final-third capabilities, Robertson is crucial to Liverpool in progressing the ball forwards, as much of their build-up is played through both their full-backs.

A player who could be seen as the biggest surprise in this list is Sampdoria’s, Tommaso Augello. The Italian has gone under the radar with his performances this season, with an impressive 11.48 progressive passes and 2.93 progressive runs per 90 both ranking very highly in our dataset.

Finally, another player who has come under much speculation at his current club, Real Madrid, is Sergio
Reguilón. The Spaniard, whose services are being chased by Everton, has completed 3.31 progressive runs, as well as 10.01 progressive passes per 90, to make for an impressive season on-loan at Sevilla.

Defensive Ability

Good full-backs can also play their part within a back four as well as provide value with their offensive ability. Although elite full-backs are incredibly important in the build-up and the attacks, sides who are pushing for the top four spots within their respective leagues should use full-backs who can trackback and contribute defensively.

The following defensive metrics look to qualify our samples ability through an analysis of successful defensive actions per 90 minutes and defensive duels success rate. This section will help us to identify individuals who are either capable of producing high defensive output or efficient in their defensive actions. The latter is useful for sides who tend to keep possession and therefore do not produce high volumes of defensive output.

Data Analysis: Scouting the LB market - key recruitment for elite clubs - statistics

The player who leads the way for defensive duels success rate is returning candidate Tommaso Augello, at a strong 74.51%. There is a decent margin between him and 2 nd place in this regard, exemplifying his effectiveness in his defensive duels. His successful defensive actions stand at 7.76 per 90, which ranks as below average, but this suggests he does not receive as much traffic down his side of the pitch.

Alternatively, the player who leads the way for successful defensive actions is Angolan Núrio Fortuna, with 16.07 per 90. Recently purchased by Gent, but played his football this term for overachievers Charleroi, it is surprising to see him produce the volume of defensive actions he has. His defensive duel success rate of 65.15% is also a great figure for a full-back.

Next up we have another returnee in the form of Max Clark. The Vitesse Arnhem player has completed a very high 14.59 successful defensive actions per 90 and has a defensive duel success rate of 66.42% in addition to his top-level ball progression.

Another player who ranks highly in both regards is French youth international Stanley Nsoki. The 21-year-old has an impressive defensive duel success rate of 68.32% and given that he faces a tough quality of opposition than the previous two names mentioned, this makes for noteworthy reading. He also completes 10.45 successful defensive actions per 90, which stands as just above average.

Lastly, AZ Alkmaar left-back Owen Wijndal shines in one of these metrics. His 70.27% defensive duels success rate ranks 2nd amongst our dataset while completing 8.37 successful defensive actions per 90. Considering AZ are a side who like to maintain high amounts of possession, this is not something that Wijndal should be criticised for.

Final-third Activity

We have now analysed some progressive and defensive data. Before we shortlist five left-backs who could be signed by an elite club and analyse them in detail, we are going to reveal which left-backs are the most effective and active in the final third. By looking at expected assists and crosses per 90 minutes, we can gather an understanding of which players are effective in their attacking contribution.

Data Analysis: Scouting the LB market - key recruitment for elite clubs - statistics

Álex Grimaldo leads the way in terms of expected assists per 90 (xA per 90), with his ability to create high-quality chances being unmatched in the dataset. His xA per 90 stands at 0.27 per 90, which is of course, excellent. He attempts an above-average figure of 3.63 crosses per 90 as well.

On the other side of the spectrum, 20-year-old Nuno Tavares leads the way for crosses per 90, with 6.79. The young Portuguese defender also ranks second for xA per 90 with 0.25, acting as an entirely capable deputy for Álex Grimaldo at Benfica.

German Philipp Max deserves a mention here, as he has excelled at creating chances for his side this term, as he has for the last few seasons at Augsburg. His 2.8 crosses per 90 have aided him in producing 0.21 xA per 90, which ranks very highly in our dataset.

It would also be worth acknowledging the final-third efforts of Spaniard Aarón Martín. Plying his trade for German outfit Mainz, Martín can consider himself unlucky this term, with zero assists as a result of his 0.19 xA per 90 he has produced. His 2.97 crosses per 90 are about league average, too.

Last of all, Angeliño, at RB Leipzig on loan from Man City, has made a decent case to return to his parent club and fight for his place in his loan spell since January. RB Leipzig look to not act on the £25 million price tag that Man City have set, despite the 23-year-old producing 0.17 xA per 90 in Germany, through his 5.52 crosses per 90.


After examining every individual across the sample concerning their individual performances across each data metric, I have managed to narrow it down to the following six individuals, who would realistically be available this summer (therefore no Robertson or Alphonso Davies). The darker the green, the higher the score.

Data Analysis: Scouting the LB market - key recruitment for elite clubs - statistics

Álex Grimaldo, LB, 24 years old, Benfica

Data Analysis: Scouting the LB market - key recruitment for elite clubs - statistics

Álex Grimaldo, the former La Masia graduate, has been the topic of much discussion regarding his future at Benfica, with many having expected him to have left the Portuguese powerhouse by this point. His technical ability is certainly one of a La Masia graduate, with his competence in his free-kicks well documented, typically scoring whenever he gets one on the edge of the box. His elite 0.27 xA per 90 is largely a result of his quick feet and good decision-making in the final third, as he is fully capable of dribbling past his man and creating a high-value goalscoring opportunity through a cutback. His market value is £28m.

Benjamin Chilwell, LB, 23 years old, Leicester City

Data Analysis: Scouting the LB market - key recruitment for elite clubs - statistics

It was mentioned earlier that Chilwell has been criticised for his performances this season, with many stating that they have been overrated. Despite this, statistically, Chilwell still stands out, at least within Europe’s top five leagues. As stated previously, his ball progression has been his strongest asset, as he likes to enter the half-space and run forward into space, and when he approaches the final-third, he prefers to whip in an early floated delivery, rather than run towards the byline. This can be seen in his 3.69 progressive runs per 90, the best in our dataset. His market value is £40m.

Pervis Estupiñán, LB, 22 years old, Osasuna (on loan from Watford)

Data Analysis: Scouting the LB market - key recruitment for elite clubs - statistics

The Ecuadorian has had a breakout season at Los Rojillos, racking up 3,201 minutes for the Spanish side, and has stood out for a team who overperformed this term, given they were newly promoted. His crossing technique is truly eye-catching, as he prefers to send in an early whipped delivery which curls in towards the head of a teammate. Similarly, to Chilwell, his progressive runs are strong at 2.95 per 90, focusing his runs down the half-space, while he attempts a high volume of crosses, at 4.84 per 90, with it being his preferred method of chance creation. His market value is £15m.

Rayan Aït-Nouri, LB, 19 years old, Angers

Data Analysis: Scouting the LB market - key recruitment for elite clubs - statistics

Now, this one might seem a bit of a stretch for an elite club but hear us out. At just 19 years old, he is more than a capable player for a team in one of Europe’s top five leagues, and he has no noticeable weakness, outside of occasionally losing the ball in possession. He is an extremely fast, skilful, and proactive defender, who likes to intensively press his opponent, but not at the cost of ruining the team’s defensive shape. His 63.96% defensive duel success rate is good and combined with his solid ball progression and final-third activity, he could grow to become a truly outstanding full-back. He may take a season to embed into an elite side, but once he is settled, that side will have a first-choice left-back sorted for the next decade. His market value is £15m.

Sergio Reguilón, LB, 23 years old, Real Madrid

Data Analysis: Scouting the LB market - key recruitment for elite clubs - statistics

The 23-year-old, who has spent the 2019/20 season on loan with Sevilla, has been a favourite of coach Julen Lopetegui ever since they worked together at Los Blancos. Rightly so, he is not a technically adept player, but he makes the most of his ability with his fantastic work ethic. His lunging slide tackles are a marvel to watch, as they seem to be perfectly timed almost every time if sometimes leaving him in no-mans land when he does miss the ball. Akin to some of the players previously mentioned, his progressive runs are strong at 3.31 progressive runs per 90, while his xA value of 0.15 per 90 is equally great, preferring to exploit the space found in the half-space and complete cutbacks from the byline. His market value is £25m.

Max Clark, LB, 24 years old, Vitesse

Data Analysis: Scouting the LB market - key recruitment for elite clubs - statistics

The final entry, Max Clark, was the most unexpected player to examine in this analysis. He ranks in the top ten of four of the six metrics we covered in detail, of course leading the way for progressive passes per 90 at 12.88. In the build-up he likes to send the ball down the line, utilising the width of the pitch and the runs of his teammates in behind. Approaching the final third, he takes a dynamic approach, choosing to either cross the ball early or utilise the half-space on a regular occasion. Labelled the ‘Next Robertson’, strong defensively, capable in the transition, and a dual-threat in the final third, he would make for a suitable replacement for Chilwell at Leicester City, if he decides to leave. His market value is £675,000.


Now we have a shortlist of players who would be able to enter the starting XI of an elite club competing in the Champions League and produce performance levels of a high standard. By using the age range of 18-26, it has allowed us to find a player coming towards their peak, who you could purchase for a reasonable fee, rather than overpaying for someone in the peak of their career.

We have also dispelled the statement of Chilwell having a subpar season in the Premier League this term, although the discussion regarding his potential transfer fee is well warranted. The question of quality within the left-back market has also been answered with several lesser-known individuals coming up high in our metrics, even some who were not shortlisted (notably, Augello, Mensah, Mohammadi, amongst others). The quality of the respective leagues should be taken into consideration when making transfer decisions, but these shortlisted players are all of high current ability, with plenty of room to improve in most cases.