Today we’ll look at players in Europe through the lens of my PATCH defensive metric. If you can’t be bothered trawling through an entire post to understand the method, you only really need to know this: PATCH measures how much a defender prevents their opponents from advancing the ball through their territory. Clearly that leaves lots of information about defenders and defences in general on the table, but you’ll have enough information by the end of this post to bash me over the head with specific examples of players you think it’s misjudging. In fact, I’ll even help you out along the way and spell out all my worries about the metric, and the things I think it ought to do in the future.

That said, in PATCH’s defence, it has some nice characteristics:

• A team’s medianish PATCH score correlates pretty well with shot numbers conceded by a team over a season, at around 0.7.
• It correlates slightly better with xG conceded by teams, at around 0.75.
• It persists year-on-year for teams, correlated at around 0.6.
• A player’s median PATCH persists year-on-year at around 0.3.

But putting numbers aside, let’s see how you feel about some individual player values. If you look at the standard deviation of median PATCH values by minutes played, you can see things settle down at around 600 minutes:

That’s because at very low values you get some weird outlying games, where players haven’t had any opponents in their territory and so score very highly. Just to be safe, we’ll set a cutoff a little higher, so here are the top European centre-backs with more than 900 minutes this season:

Competition	Team	Player	PATCH
Italian Serie A	Fiorentina	Gonzalo Rodríguez	6.27
French Ligue 1	Lyon	Samuel Umtiti	5.79
Spanish La Liga	Real Madrid	Pepe	5.52
Spanish La Liga	Barcelona	Gerard Piqué	5.24
German Bundesliga	FC Bayern München	Jerome Boateng	5.20
Spanish La Liga	Barcelona	Javier Mascherano	5.20
Spanish La Liga	Málaga	Raúl Albentosa	5.19
Italian Serie A	Roma	Kostas Manolas	5.06
Italian Serie A	Lazio	Wesley Hoedt	4.99
German Bundesliga	Borussia Dortmund	Sokratis	4.94
Italian Serie A	Fiorentina	Davide Astori	4.91
French Ligue 1	Paris Saint-Germain	Thiago Silva	4.86
English Premier League	Liverpool	Martin Skrtel	4.72
English Premier League	Liverpool	Mamadou Sakho	4.72
Italian Serie A	Internazionale	Jeison Murillo	4.71
Italian Serie A	Milan	Alex	4.66
Italian Serie A	Juventus	Andrea Barzagli	4.63
French Ligue 1	St Etienne	Loic Perrin	4.59
French Ligue 1	GFC Ajaccio	Roderic Filippi	4.57
Italian Serie A	Juventus	Leonardo Bonucci	4.49

There are some clumps of teams here, so we should immediately be suspicious that we’re measuring team effects as much as player effects – PATCH currently doesn’t adjust for teams average scores, and for that matter nor does it score leagues differently. But these numbers are mostly defensible. It’s fun to note that Raúl Albentosa was a Derby County signing during Steve McClaren’s reign, and he’s recently been targeting Samuel Umtiti at Newcastle, so it’s nice to know I’ve built the perfect metric for him, even if you don’t buy it.

The same metric works for defensive and centre midfielders too:

Competition	Team	Player	PATCH
Spanish La Liga	Barcelona	Sergio Busquets	5.66
French Ligue 1	Lyon	Maxime Gonalons	5.50
Spanish La Liga	Barcelona	Ivan Rakitic	5.21
Italian Serie A	Fiorentina	Milan Badelj	5.19
Italian Serie A	Roma	Daniele De Rossi	4.84
French Ligue 1	Lyon	Corentin Tolisso	4.81
Italian Serie A	Fiorentina	Borja Valero	4.60
Italian Serie A	Fiorentina	Matias Vecino	4.48
Spanish La Liga	Sevilla	Grzegorz Krychowiak	4.45
Italian Serie A	Lazio	Lucas Biglia	4.31
Italian Serie A	Internazionale	Felipe Melo	4.30
Spanish La Liga	Las Palmas	Vicente Gómez	4.28
English Premier League	Liverpool	Emre Can	4.26
Spanish La Liga	Sevilla	Steven N’Zonzi	4.26
German Bundesliga	Borussia Dortmund	Ilkay Gündogan	4.26
Italian Serie A	Roma	Radja Nainggolan	4.25
German Bundesliga	FC Bayern München	Xabi Alonso	4.24
German Bundesliga	FC Bayern München	Arturo Vidal	4.11
Spanish La Liga	Rayo Vallecano	Raúl Baena	4.10
English Premier League	Liverpool	Jordan Henderson	4.09

Busquets on top, all is right in the world.

Prospects

We can already see some talented youngsters in the tables above, so let’s focus purely on players that were 23 or under at the start of this season. I’ve relaxed the minutes to 600, here’s the top 30, taken from all midfielders and defenders:

Competition	Team	Player	Date of Birth	Minutes	PATCH
French Ligue 1	Lyon	Samuel Umtiti	14/11/1993	1852	5.79
Italian Serie A	Lazio	Wesley Hoedt	06/03/1994	1507	4.99
French Ligue 1	Lyon	Corentin Tolisso	03/08/1994	2188	4.63
German Bundesliga	FC Bayern München	Joshua Kimmich	08/02/1995	727	4.54
English Premier League	Liverpool	Emre Can	12/01/1994	2054	4.44
German Bundesliga	VfB Stuttgart	Timo Baumgartl	04/03/1996	1287	4.30
German Bundesliga	Bayer 04 Leverkusen	Jonathan Tah	11/02/1996	2076	4.27
French Ligue 1	Lyon	Sergi Darder	22/12/1993	696	4.15
German Bundesliga	VfL Wolfsburg	Maximilian Arnold	27/05/1994	877	4.10
German Bundesliga	FC Bayern München	Kingsley Coman	13/06/1996	895	3.98
Spanish La Liga	Rayo Vallecano	Diego Llorente	16/08/1993	2228	3.97
French Ligue 1	Paris Saint-Germain	Marquinhos	14/05/1994	988	3.95
Italian Serie A	Empoli	Federico Barba	01/09/1993	927	3.93
English Premier League	Tottenham Hotspur	Dele Alli	11/04/1996	730	3.93
English Premier League	Tottenham Hotspur	Eric Dier	15/01/1994	2375	3.79
English Premier League	Arsenal	Héctor Bellerín	19/03/1995	2346	3.79
Spanish La Liga	Real Sociedad	Aritz Elustondo	11/01/1994	1643	3.68
Spanish La Liga	Atlético de Madrid	Saúl Ñíguez	21/11/1994	1337	3.66
Italian Serie A	Lazio	Sergej Milinkovic-Savic	27/02/1995	715	3.65
French Ligue 1	Monaco	Wallace	14/10/1994	1654	3.63
German Bundesliga	Borussia Dortmund	Matthias Ginter	19/01/1994	1414	3.62
Italian Serie A	Milan	Alessio Romagnoli	12/01/1995	2102	3.62
German Bundesliga	Borussia Dortmund	Julian Weigl	08/09/1995	1575	3.59
Italian Serie A	Lazio	Danilo Cataldi	06/08/1994	1024	3.55
Italian Serie A	Napoli	Elseid Hysaj	02/02/1994	2279	3.52
Spanish La Liga	Sevilla	Sebastián Cristóforo	23/08/1993	614	3.51
English Premier League	Chelsea	Kurt Zouma	27/10/1994	1949	3.51
French Ligue 1	Nice	Olivier Boscagli	18/11/1997	792	3.48
Spanish La Liga	Getafe	Emiliano Velázquez	30/04/1994	745	3.44
Italian Serie A	Sampdoria	David Ivan	26/02/1995	785	3.41

Note: the tables above filter to performances at centre-back or in midfield, if the values differ in this last table it’s because it considers their performances in a wider variety of positions.

So, cheer up Timo Baumgartl, PATCH doesn’t count mistakes. You’ll note again big clumps of players from the same teams (kudos, Lyon) – we know by now we’re probably measuring some systematic effects here. It’s also worth pointing out that if a young player is getting this level of minutes, in the big 5 leagues, they’re probably at a certain level without even looking at their numbers. But again, at first glance, this is a decent list.

Liverpool’s First Choice Centre-Backs

At the Opta Pro Forum I blurted out to the Liverpool contingent that my pet defensive metric quite liked their defending, to which they replied “ours doesn’t.” So I was a little crestfallen, but I’ll continue to talk myself out of a job here: Liverpool concede the second fewest shots in the league, so I’m right. They also have the worst save percentage in the league but nevertheless renewed Mignolet’s contract, so they’re wrong. QED. Let’s look more closely:

Here you’ve got all Liverpool’s games this season – Rodgers up to the fateful Merseryside derby on the 4th October, Klopp soon after. The markers show individual PATCH performances, and the lines are five-game moving averages (although Touré isn’t quite there yet). The average PATCH for EPL centre-backs is around 3.3, and you’ll note that Liverpool are regularly exceeding that. You can also see that Skrtel had some insane outliers, but maintained pretty good form for Klopp until his injury (which – if you’re to believe renowned fitness troll Raymond Verheijen – was inevitable). The fight for second place is closer, but even taking Lovren and Sakho side-by-side, I don’t believe you’re left with a terrible pairing.

So, I don’t believe Liverpool’s defence is terrible and I think they have a solid foundation both in defence and midfield for Klopp to build on over the next season. I do believe they’ve been unlucky, as James Yorke points out in this article on Statsbomb. It’s funny to compare Everton and Liverpool’s defences this season – they both sit on 36 goals conceded in the league. Tim Howard has taken a lot of heat this year for his performances, all while facing 4.7 shots on target a game – the fourth worst in the league. Mignolet’s been facing 3.3 – the second least. While Howard has now been unceremoniously dropped and is soon to be shipped off to the MLS, Mignolet gets his contract renewed. Sure, some of of this is luck and not entirely his fault, but I genuinely believe you should not lay the blame on Liverpool’s defence, there’s not a lot more they could do to make Mignolet’s life quieter.

Arsenal’s Midfield

Through injuries, sentimentality or pure stubbornness, it’s hard to tell if Wenger knows his best midfield this season. I asked on Twitter and a lively debate ensued, but excluding the lamentation of Wilshere believers, the most common answer was Coquelin & Cazorla, with some pondering ways to insert Ramsey into the mix. What does PATCH think, purely defensively, of their appearances in the centre of the field?

Okay, well, first thoughts are that this is a graph format looking to get retired early, but here you have the four players who have put reasonable minutes into Arsenal’s central midfield, with the markers again showing their PATCH values in each game week, and the lines again showing a five game moving average. The average PATCH for a midfielder in the EPL is basically the same as a defender, around 3.3. This graph seems to imply that Cazorla has very good and very average games, and similar could be said for Flamini. Ramsey doesn’t seem like anything special, but is pretty low-variance. Coquelin seemed to start the season very strongly, but was fairly average in the lead-up to his injury.

Let’s break it down more simply, here are the averages:

Player	PATCH
Santiago Cazorla	4.17
Francis Coquelin	3.83
Mathieu Flamini	3.79
Aaron Ramsey	3.60

So in black and white, we seem to more or less agree with Arsenal fans’ instincts.

N’Golo Kanté

What of players whose defending we rave about but who don’t make an appearance high up the PATCH ratings? N’Golo Kanté is way down the list, with a very middling  3.12. What’s happened there? Well, let me reiterate that PATCH measures territory and ball progression, nothing else. As I mentioned on the Analytics FC podcast recently, not all ball progression is bad. Much has been made of Leicester’s “bend, don’t break” defensive scheme this season – they give up territory but their low block often makes up for it, this means their midfield isn’t likely to score highly for repelling the opponent. Kanté himself regularly relies on pace and last ditch tackles (and he is an excellent tackler) to retrieve the ball once it’s in his territory, but if a pass has been completed in that territory, PATCH has already given him a demerit.

So… PATCH is useless because it misses demonstrably good players? Well, I’m not sure I’d go as far as calling Leicester’s defence bad, but it’s certainly well below par for a league leader, as Tim at 7amkickoff recently analysed. That said, I’ll admit I’m a little uncomfortable. I’ve said elsewhere, the essence of PATCH, or really any defensive metric, is this:

1. Whose fault is it?
2. How bad is it?

In PATCH, the whose fault part is calculated by territory (and there are lots of ways to do this better) and the how bad bit is done through ball progression. Alternatives to the second might pick Kanté up better – how many moves enter his territory, but never leave? That would be an interesting one to look at, and something I’ll explore soon.

For now, let’s just say that he’s valuable for Leicester inasmuch as his defensive skills turn into attacks very effectively, because it’s Leicester’s attack (and let’s face it, their luck) that is powering their title challenge, and not necessarily their defence. And that, dear reader, is another thing that PATCH doesn’t measure in defenders.

Conclusion

Hopefully if you’ve got this far, you believe there’s value in something like PATCH as a way of measuring defenders. It’s certainly entangled with teams’ systematic effects, and we suspect it has some false negatives. I don’t think looking at these outputs that there are tons of false positives however, but then Flamini rears his head so who knows.

I’m constantly working on PATCH, so I’d love to hear your ideas for places it might fall down, or things you’d like to see it applied to. To that end, I’ve bunged PATCH values for all EPL performances this season on Github. This file contains:

1. Team
2. Opposition
3. Match date
4. Player
5. Date of Birth
6. Nationality
7. Starting lineup X position
8. Starting lineup Y position
9. Minutes played
10. PATCH

Play, critique, ignore, do what you will. I’ll see if I can get to the point where these are updated for a all players in a bunch of leagues every week, but right now I can’t guarantee the scoring is going to be at all stable with all the changes I’m making.